diff --git a/desktop/package.json b/desktop/package.json
index a1fd2e919d..c3f9de8f62 100644
--- a/desktop/package.json
+++ b/desktop/package.json
@@ -64,6 +64,7 @@
     "clsx": "^2.1.1",
     "embla-carousel-react": "^8.6.0",
     "emoji-mart": "^5.6.0",
+    "i18next": "^25.10.5",
     "jdenticon": "^3.3.0",
     "lucide-react": "^1.0.0",
     "motion": "^12.38.0",
@@ -72,6 +73,7 @@
     "react": "^19.1.0",
     "react-diff-view": "^3.3.2",
     "react-dom": "^19.1.0",
+    "react-i18next": "^16.6.2",
     "react-markdown": "^10.1.0",
     "remark-breaks": "^4.0.0",
     "remark-gfm": "^4.0.1",
diff --git a/desktop/src/features/agents/ui/AgentsView.tsx b/desktop/src/features/agents/ui/AgentsView.tsx
index f9ada91c2f..f80a08d1fd 100644
--- a/desktop/src/features/agents/ui/AgentsView.tsx
+++ b/desktop/src/features/agents/ui/AgentsView.tsx
@@ -1,4 +1,5 @@
 import * as React from "react";
+import { useTranslation } from "react-i18next";
 import { EllipsisVertical, OctagonX, Settings2 } from "lucide-react";
 import {
   consumePendingSnapshotImport,
@@ -39,6 +40,7 @@ import { PageHeader } from "@/shared/ui/PageHeader";
 import { getInheritedAgentDefaults } from "./bakedEnvHelpers";
 
 export function AgentsView() {
+  const { t } = useTranslation();
   const { openPersonaProfilePanel, openProfilePanel } = useProfilePanel();
   const { globalConfig } = useGlobalAgentConfig();
   const { data: bakedEnv } = useBakedBuildEnvQuery({ enabled: true });
@@ -150,8 +152,8 @@ export function AgentsView() {
                   >
                     <Settings2 />
                     {hasSavedAgentDefaults
-                      ? "Agent defaults"
-                      : "Set agent defaults"}
+                      ? t("agents.defaults")
+                      : t("agents.setDefaults")}
                   </Button>
                   {runningAgentCount > 0 ? (
                     <Button
@@ -163,7 +165,7 @@ export function AgentsView() {
                       variant="outline"
                     >
                       <OctagonX />
-                      Stop running agents
+                      {t("agents.stopRunning")}
                     </Button>
                   ) : null}
                 </div>
@@ -171,7 +173,7 @@ export function AgentsView() {
                 <DropdownMenu modal={false}>
                   <DropdownMenuTrigger asChild>
                     <Button
-                      aria-label="Agent actions"
+                      aria-label={t("agents.actions")}
                       className="hidden [@container(max-width:40rem)]:inline-flex"
                       data-testid="agent-actions-menu-trigger"
                       ref={compactActionsTriggerRef}
@@ -190,8 +192,8 @@ export function AgentsView() {
                     >
                       <Settings2 />
                       {hasSavedAgentDefaults
-                        ? "Agent defaults"
-                        : "Set agent defaults"}
+                        ? t("agents.defaults")
+                        : t("agents.setDefaults")}
                     </DropdownMenuItem>
                     {runningAgentCount > 0 ? (
                       <DropdownMenuItem
@@ -201,15 +203,15 @@ export function AgentsView() {
                         }}
                       >
                         <OctagonX />
-                        Stop running agents
+                        {t("agents.stopRunning")}
                       </DropdownMenuItem>
                     ) : null}
                   </DropdownMenuContent>
                 </DropdownMenu>
               </>
             }
-            description="Set up and manage your agents."
-            title="Agents"
+            description={t("agents.description")}
+            title={t("agents.title")}
           />
           <div className="flex flex-col gap-8">
             <UnifiedAgentsSection
diff --git a/desktop/src/features/agents/ui/UnifiedAgentsSection.tsx b/desktop/src/features/agents/ui/UnifiedAgentsSection.tsx
index 212d9bc96e..b4c433b2fd 100644
--- a/desktop/src/features/agents/ui/UnifiedAgentsSection.tsx
+++ b/desktop/src/features/agents/ui/UnifiedAgentsSection.tsx
@@ -1,4 +1,5 @@
 import * as React from "react";
+import { useTranslation } from "react-i18next";
 import { AlertTriangle, ChevronDown, ChevronRight } from "lucide-react";
 
 import { resolveAgentCardModelLabel } from "@/features/agents/lib/agentCardModelLabel";
@@ -68,6 +69,7 @@ export const AGENT_CARD_GRID_COLUMNS_CLASS =
 export const IDENTITY_CARD_GRID_CLASS = `${AGENT_CARD_COLUMN_CLASS} ${AGENT_CARD_GRID_COLUMNS_CLASS} grid justify-start gap-3 [@container(max-width:40rem)]:justify-center`;
 
 export function UnifiedAgentsSection(props: UnifiedAgentsSectionProps) {
+  const { t } = useTranslation();
   const {
     actionErrorMessage,
     actionNoticeMessage,
@@ -135,7 +137,7 @@ export function UnifiedAgentsSection(props: UnifiedAgentsSectionProps) {
       {isDragOver ? (
         <div className="pointer-events-none absolute -inset-1 z-10 flex items-center justify-center rounded-2xl border-2 border-dashed border-primary/50 bg-background/80 backdrop-blur-sm">
           <p className="text-sm font-medium text-primary">
-            Drop .agent.json or .agent.png to import
+            {t("agents.dropToImport")}
           </p>
         </div>
       ) : null}
@@ -203,7 +205,7 @@ export function UnifiedAgentsSection(props: UnifiedAgentsSectionProps) {
               collapsed={collapsed}
               defaultModel={defaultModel}
               groupKey="__unknown__"
-              label="Unknown agents"
+              label={t("agents.unknown")}
               restartingAgentPubkey={restartingAgentPubkey}
               startingAgentPubkey={startingAgentPubkey}
               onToggle={toggle}
@@ -218,7 +220,7 @@ export function UnifiedAgentsSection(props: UnifiedAgentsSectionProps) {
               collapsed={collapsed}
               defaultModel={defaultModel}
               groupKey="__ungrouped__"
-              label="Custom agents"
+              label={t("agents.custom")}
               restartingAgentPubkey={restartingAgentPubkey}
               startingAgentPubkey={startingAgentPubkey}
               onToggle={toggle}
@@ -281,6 +283,7 @@ function AgentPersonaCard({
   onStartAgent: (pubkey: string) => void;
   onStartPersona: (persona: AgentPersona) => void;
 }) {
+  const { t } = useTranslation();
   const title = persona.displayName;
   const modelLabel = resolveAgentCardModelLabel({
     agent,
@@ -303,7 +306,7 @@ function AgentPersonaCard({
         avatarUrl,
         Boolean(agent && !persona.avatarUrl && profileQuery.isPending),
       )}
-      ariaLabel={`${title} agent profile`}
+      ariaLabel={t("agents.profile", { name: title })}
       avatar={
         agent ? (
           <AgentRuntimeAvatarControl
@@ -356,7 +359,7 @@ function AgentPersonaCard({
         agent?.personaOrphaned ? (
           <Badge className="gap-1" variant="warning">
             <AlertTriangle className="h-3 w-3" />
-            Configuration missing
+            {t("agents.configurationMissing")}
           </Badge>
         ) : null
       }
@@ -384,6 +387,7 @@ function StandaloneAgentCard({
   onRestartAgent: (pubkey: string) => void;
   onStartAgent: (pubkey: string) => void;
 }) {
+  const { t } = useTranslation();
   const title = agent.name;
   const profileQuery = useUserProfileQuery(agent.pubkey);
   const friendlyError = friendlyAgentLastError(
@@ -395,7 +399,7 @@ function StandaloneAgentCard({
 
   return (
     <AgentIdentityCard
-      ariaLabel={`${title} agent profile`}
+      ariaLabel={t("agents.profile", { name: title })}
       avatar={
         <AgentRuntimeAvatarControl
           activeTestId={`agent-runtime-active-${agent.pubkey}`}
@@ -436,7 +440,7 @@ function StandaloneAgentCard({
         agent.personaOrphaned ? (
           <Badge className="gap-1" variant="warning">
             <AlertTriangle className="h-3 w-3" />
-            Configuration missing
+            {t("agents.configurationMissing")}
           </Badge>
         ) : null
       }
@@ -465,27 +469,31 @@ function NewAgentCard({
   onDiscover: () => void;
   onImport: () => void;
 }) {
+  const { t } = useTranslation();
   return (
     <DropdownMenu modal={false}>
       <DropdownMenuTrigger asChild>
-        <CreateIdentityCard ariaLabel="New agent" dataTestId="new-agent-card" />
+        <CreateIdentityCard
+          ariaLabel={t("agents.newAgent")}
+          dataTestId="new-agent-card"
+        />
       </DropdownMenuTrigger>
       <DropdownMenuContent
         align="start"
         onCloseAutoFocus={(event) => event.preventDefault()}
       >
         <DropdownMenuItem disabled={isPending} onClick={onCreate}>
-          Create agent
+          {t("agents.createAgent")}
         </DropdownMenuItem>
         <DropdownMenuItem disabled={isPending} onClick={onDiscover}>
-          Discover agents
+          {t("agents.discoverAgents")}
         </DropdownMenuItem>
         <DropdownMenuItem
           data-testid="import-agent-snapshot-menu-item"
           disabled={isPending}
           onClick={onImport}
         >
-          Import
+          {t("agents.import")}
         </DropdownMenuItem>
       </DropdownMenuContent>
     </DropdownMenu>
diff --git a/desktop/src/features/communities/ui/CommunitySwitcher.tsx b/desktop/src/features/communities/ui/CommunitySwitcher.tsx
index cd530e6908..3aceaa5148 100644
--- a/desktop/src/features/communities/ui/CommunitySwitcher.tsx
+++ b/desktop/src/features/communities/ui/CommunitySwitcher.tsx
@@ -12,6 +12,7 @@ import {
 } from "lucide-react";
 import * as React from "react";
 import { toast } from "sonner";
+import { useTranslation } from "react-i18next";
 
 import type { LeaveCommunityResult } from "@/features/communities/leaveCommunity";
 import type { Community } from "@/features/communities/types";
@@ -39,13 +40,13 @@ import { writeTextToClipboard } from "@/shared/lib/clipboard";
 import { useActiveCommunityIcon } from "@/features/communities/useCommunityIcons";
 import { EditCommunityDialog } from "./EditCommunityDialog";
 
-const CONNECTION_STATE_LABEL: Record<ConnectionState, string> = {
-  idle: "Not connected",
-  connecting: "Connecting…",
-  connected: "Connected",
-  reconnecting: "Reconnecting to relay…",
-  stalled: "Connection lost — relay is not responding",
-  disconnected: "Disconnected from relay",
+const CONNECTION_STATE_LABEL_KEY: Record<ConnectionState, string> = {
+  idle: "sidebar.community.notConnected",
+  connecting: "sidebar.community.connecting",
+  connected: "sidebar.community.connected",
+  reconnecting: "sidebar.community.reconnecting",
+  stalled: "sidebar.community.stalled",
+  disconnected: "sidebar.community.disconnected",
 };
 
 type CommunitySwitcherProps = {
@@ -103,6 +104,7 @@ export function CommunitySwitcher({
   onUpdateCommunity,
   onRemoveCommunity,
 }: CommunitySwitcherProps) {
+  const { t } = useTranslation();
   const [editingCommunity, setEditingCommunity] =
     React.useState<Community | null>(null);
   const [dropdownOpen, setDropdownOpen] = React.useState(false);
@@ -111,7 +113,7 @@ export function CommunitySwitcher({
   const profileMenuHoverTimer = React.useRef<number | null>(null);
   const connectionState = useRelayConnection();
   const degraded = isRelayConnectionDegraded(connectionState);
-  const connectionLabel = CONNECTION_STATE_LABEL[connectionState];
+  const connectionLabel = t(CONNECTION_STATE_LABEL_KEY[connectionState]);
   const activeIconQuery = useActiveCommunityIcon(activeCommunity?.relayUrl);
   const activeIcon = activeIconQuery.data ?? null;
   const isProfileVariant = variant === "profile";
@@ -221,7 +223,7 @@ export function CommunitySwitcher({
             : "min-w-0 flex-1 truncate font-medium"
         }
       >
-        {activeCommunity?.name ?? "No community"}
+        {activeCommunity?.name ?? t("sidebar.community.noCommunity")}
       </span>
       {variant === "profile-menu" ? (
         <ChevronRight className="h-4 w-4 shrink-0 text-muted-foreground" />
@@ -246,8 +248,8 @@ export function CommunitySwitcher({
             aria-haspopup="menu"
             aria-label={
               degraded
-                ? `${activeCommunity?.name ?? "Community"} — ${connectionLabel}`
-                : "Community actions"
+                ? `${activeCommunity?.name ?? t("sidebar.community.community")} — ${connectionLabel}`
+                : t("sidebar.community.actions")
             }
             className="flex w-full items-center gap-2 rounded-lg px-3 py-2 text-left text-sm text-popover-foreground outline-hidden transition-colors hover:bg-muted/50 focus:bg-muted/50 focus:outline-none focus-visible:bg-muted/50 focus-visible:outline-none data-[state=open]:bg-muted/50 data-[state=open]:text-popover-foreground"
             data-testid="community-switcher"
@@ -269,7 +271,7 @@ export function CommunitySwitcher({
           sideOffset={0}
         >
           <div
-            aria-label="Community actions"
+            aria-label={t("sidebar.community.actions")}
             data-testid="profile-community-actions"
             role="menu"
           >
@@ -285,7 +287,7 @@ export function CommunitySwitcher({
                   type="button"
                 >
                   <Link2 className="h-4 w-4" />
-                  <span>Copy community URL</span>
+                  <span>{t("sidebar.community.copyUrl")}</span>
                 </button>
                 {canInvite && onInvite ? (
                   <button
@@ -298,7 +300,7 @@ export function CommunitySwitcher({
                     type="button"
                   >
                     <Ticket className="h-4 w-4" />
-                    <span>Invite to community</span>
+                    <span>{t("sidebar.community.invite")}</span>
                   </button>
                 ) : null}
                 <button
@@ -311,7 +313,7 @@ export function CommunitySwitcher({
                   type="button"
                 >
                   <Settings2 className="h-4 w-4" />
-                  <span>Community settings</span>
+                  <span>{t("sidebar.community.settings")}</span>
                 </button>
                 <button
                   className="flex min-h-9 w-full items-center gap-2 rounded-lg px-3 py-2 text-left text-sm text-destructive outline-hidden transition-colors hover:bg-destructive/10 focus:bg-destructive/10 focus:outline-none focus-visible:bg-destructive/10 focus-visible:outline-none disabled:pointer-events-none disabled:opacity-50"
@@ -344,7 +346,7 @@ export function CommunitySwitcher({
               type="button"
             >
               <Plus className="h-4 w-4" />
-              <span>Add a community</span>
+              <span>{t("sidebar.community.add")}</span>
             </button>
           </div>
         </PopoverContent>
@@ -362,8 +364,8 @@ export function CommunitySwitcher({
           <button
             aria-label={
               degraded
-                ? `${activeCommunity?.name ?? "Community"} — ${connectionLabel}`
-                : "Switch community"
+                ? `${activeCommunity?.name ?? t("sidebar.community.community")} — ${connectionLabel}`
+                : t("sidebar.community.switch")
             }
             className="flex min-w-0 max-w-full items-center gap-1.5 rounded-md py-0.5 text-left text-xs text-sidebar-foreground/50 outline-hidden transition-colors hover:text-sidebar-foreground focus:outline-none focus-visible:outline-none data-[state=open]:text-sidebar-foreground"
             data-testid="community-switcher"
@@ -375,7 +377,7 @@ export function CommunitySwitcher({
           <SidebarMenuButton
             aria-label={
               degraded
-                ? `${activeCommunity?.name ?? "Community"} — ${connectionLabel}`
+                ? `${activeCommunity?.name ?? t("sidebar.community.community")} — ${connectionLabel}`
                 : undefined
             }
             className="h-auto gap-2 rounded-xl px-2.5 py-2 data-[state=open]:bg-sidebar-accent"
@@ -408,7 +410,9 @@ export function CommunitySwitcher({
             </span>
             <span className="min-w-0 flex-1 truncate">{community.name}</span>
             <button
-              aria-label={`Edit ${community.name}`}
+              aria-label={t("sidebar.community.edit", {
+                name: community.name,
+              })}
               className="flex h-5 w-5 shrink-0 items-center justify-center rounded opacity-0 hover:bg-accent group-hover:opacity-100 group-focus:opacity-100"
               onClick={(e) => {
                 e.stopPropagation();
@@ -425,7 +429,7 @@ export function CommunitySwitcher({
         <DropdownMenuSeparator />
         <DropdownMenuItem onSelect={onAddCommunity}>
           <Plus className="h-4 w-4" />
-          <span>Add a community</span>
+          <span>{t("sidebar.community.add")}</span>
         </DropdownMenuItem>
       </DropdownMenuContent>
     </DropdownMenu>
diff --git a/desktop/src/features/messages/ui/ComposerReplyEditBanner.tsx b/desktop/src/features/messages/ui/ComposerReplyEditBanner.tsx
index 485d11de28..da61d4a6ab 100644
--- a/desktop/src/features/messages/ui/ComposerReplyEditBanner.tsx
+++ b/desktop/src/features/messages/ui/ComposerReplyEditBanner.tsx
@@ -1,4 +1,5 @@
 import { CornerUpLeft, Pencil, X } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import { cn } from "@/shared/lib/cn";
 import { Button } from "@/shared/ui/button";
@@ -25,6 +26,7 @@ export function ComposerReplyEditBanner({
   onCancelEdit?: () => void;
   onCancelReply?: () => void;
 }) {
+  const { t } = useTranslation();
   if (isEditing) {
     return (
       <div
@@ -34,12 +36,12 @@ export function ComposerReplyEditBanner({
         <Pencil aria-hidden className="h-4 w-4 shrink-0" />
         <div className="min-w-0 flex-1">
           <p className="truncate font-medium text-foreground">
-            Editing message
+            {t("composer.banner.editing")}
           </p>
         </div>
         {onCancelEdit ? (
           <Button
-            aria-label="Cancel edit"
+            aria-label={t("composer.banner.cancelEdit")}
             className="-mr-1 h-7 w-7 shrink-0 px-0 text-muted-foreground hover:text-foreground"
             disabled={isEditCancelDisabled}
             onClick={onCancelEdit}
@@ -63,7 +65,7 @@ export function ComposerReplyEditBanner({
         <CornerUpLeft aria-hidden className="mt-0.5 h-4 w-4 shrink-0" />
         <div className="min-w-0 flex-1">
           <p className="truncate font-medium text-foreground">
-            Replying to {replyTarget.author}
+            {t("composer.banner.replying", { author: replyTarget.author })}
           </p>
           {replyTarget.body ? (
             <p className="truncate text-muted-foreground/80">
@@ -73,7 +75,7 @@ export function ComposerReplyEditBanner({
         </div>
         {onCancelReply ? (
           <Button
-            aria-label="Cancel reply"
+            aria-label={t("composer.banner.cancelReply")}
             className="-mr-1 h-7 w-7 shrink-0 px-0 text-muted-foreground hover:text-foreground"
             onClick={onCancelReply}
             size="icon"
diff --git a/desktop/src/features/messages/ui/DeleteMessageConfirmDialog.tsx b/desktop/src/features/messages/ui/DeleteMessageConfirmDialog.tsx
index 9802f09efc..015a39dc7f 100644
--- a/desktop/src/features/messages/ui/DeleteMessageConfirmDialog.tsx
+++ b/desktop/src/features/messages/ui/DeleteMessageConfirmDialog.tsx
@@ -9,6 +9,7 @@ import {
   AlertDialogTitle,
 } from "@/shared/ui/alert-dialog";
 import { Button } from "@/shared/ui/button";
+import { useTranslation } from "react-i18next";
 
 /**
  * The "Delete message?" confirmation. Single definition shared by every
@@ -26,24 +27,25 @@ export function DeleteMessageConfirmDialog({
   onOpenChange: (open: boolean) => void;
   onConfirm: () => void;
 }) {
+  const { t } = useTranslation();
   return (
     <AlertDialog onOpenChange={onOpenChange} open={open}>
       <AlertDialogContent>
         <AlertDialogHeader>
-          <AlertDialogTitle>Delete message?</AlertDialogTitle>
+          <AlertDialogTitle>{t("composer.delete.title")}</AlertDialogTitle>
           <AlertDialogDescription>
-            This will permanently delete this message and cannot be undone.
+            {t("composer.delete.description")}
           </AlertDialogDescription>
         </AlertDialogHeader>
         <AlertDialogFooter>
           <AlertDialogCancel asChild>
             <Button type="button" variant="outline">
-              Cancel
+              {t("composer.delete.cancel")}
             </Button>
           </AlertDialogCancel>
           <AlertDialogAction asChild>
             <Button onClick={onConfirm} type="button" variant="destructive">
-              Delete
+              {t("composer.delete.confirm")}
             </Button>
           </AlertDialogAction>
         </AlertDialogFooter>
diff --git a/desktop/src/features/messages/ui/FormattingToolbar.tsx b/desktop/src/features/messages/ui/FormattingToolbar.tsx
index afe2cb22a5..94912c56de 100644
--- a/desktop/src/features/messages/ui/FormattingToolbar.tsx
+++ b/desktop/src/features/messages/ui/FormattingToolbar.tsx
@@ -13,6 +13,7 @@ import {
   SquareCode,
   Strikethrough,
 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import { cn } from "@/shared/lib/cn";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/shared/ui/tooltip";
@@ -129,6 +130,7 @@ export const FormattingToolbar = React.memo(function FormattingToolbar({
   disabled = false,
   onLinkButton,
 }: FormattingToolbarProps) {
+  const { t } = useTranslation();
   const pendingSelectionRef = React.useRef<FormattingSelectionRange | null>(
     null,
   );
@@ -254,18 +256,18 @@ export const FormattingToolbar = React.memo(function FormattingToolbar({
     const hasSelection = from !== to;
 
     if (hasSelection) {
-      const url = window.prompt("Enter URL:");
+      const url = window.prompt(t("composer.format.enterUrl"));
       if (url) {
         editor.chain().focus().setLink({ href: url }).run();
       }
     } else {
-      const url = window.prompt("Enter URL:");
+      const url = window.prompt(t("composer.format.enterUrl"));
       if (url) {
-        const label = window.prompt("Link text:", url) || url;
+        const label = window.prompt(t("composer.format.linkText"), url) || url;
         editor.chain().focus().insertContent(`[${label}](${url})`).run();
       }
     }
-  }, [editor, formattingChain, onLinkButton, restorePendingSelection]);
+  }, [editor, formattingChain, onLinkButton, restorePendingSelection, t]);
 
   const toggleBulletList = React.useCallback(() => {
     formattingChain()
@@ -320,66 +322,66 @@ export const FormattingToolbar = React.memo(function FormattingToolbar({
   const items = [
     {
       icon: Bold,
-      label: "Bold",
+      label: t("composer.format.bold"),
       shortcut: "⌘B",
       action: toggleBold,
       active: activeStates.bold,
     },
     {
       icon: Italic,
-      label: "Italic",
+      label: t("composer.format.italic"),
       shortcut: "⌘I",
       action: toggleItalic,
       active: activeStates.italic,
     },
     {
       icon: Strikethrough,
-      label: "Strikethrough",
+      label: t("composer.format.strikethrough"),
       shortcut: "⌘⇧X",
       action: toggleStrike,
       active: activeStates.strike,
     },
     {
       icon: Code,
-      label: "Code",
+      label: t("composer.format.code"),
       shortcut: "⌘E",
       action: toggleCode,
       active: activeStates.code,
     },
     {
       icon: SquareCode,
-      label: "Code block",
+      label: t("composer.format.codeBlock"),
       action: toggleCodeBlock,
       active: activeStates.codeBlock,
     },
     {
       icon: Link,
-      label: "Link",
+      label: t("composer.format.link"),
       shortcut: "⌘K",
       action: toggleLink,
       active: activeStates.link,
     },
     {
       icon: List,
-      label: "Bullet list",
+      label: t("composer.format.bulletList"),
       action: toggleBulletList,
       active: activeStates.bulletList,
     },
     {
       icon: ListOrdered,
-      label: "Ordered list",
+      label: t("composer.format.orderedList"),
       action: toggleOrderedList,
       active: activeStates.orderedList,
     },
     {
       icon: Quote,
-      label: "Quote",
+      label: t("composer.format.quote"),
       action: toggleBlockquote,
       active: activeStates.blockquote,
     },
     {
       icon: HatGlasses,
-      label: "Spoiler",
+      label: t("composer.format.spoiler"),
       action: toggleSpoiler,
       active: activeStates.spoiler,
     },
diff --git a/desktop/src/features/messages/ui/MentionAutocomplete.tsx b/desktop/src/features/messages/ui/MentionAutocomplete.tsx
index 508e35f402..58c4910d51 100644
--- a/desktop/src/features/messages/ui/MentionAutocomplete.tsx
+++ b/desktop/src/features/messages/ui/MentionAutocomplete.tsx
@@ -1,4 +1,5 @@
 import * as React from "react";
+import { useTranslation } from "react-i18next";
 import { Bot, Users } from "lucide-react";
 import type { TeamMentionMember } from "@/features/messages/lib/mentionCandidates";
 
@@ -42,6 +43,7 @@ export const MentionAutocomplete = React.memo(function MentionAutocomplete({
   onSelect,
   position = "above",
 }: MentionAutocompleteProps) {
+  const { t } = useTranslation();
   const listRef = React.useRef<HTMLDivElement>(null);
 
   React.useEffect(() => {
@@ -100,7 +102,7 @@ export const MentionAutocomplete = React.memo(function MentionAutocomplete({
             (suggestion.personaId ? `persona-${suggestion.personaId}` : null) ??
             (suggestion.teamId ? `team-${suggestion.teamId}` : null) ??
             suggestion.displayName;
-          const agentLabel = "agent";
+          const agentLabel = t("composer.mention.agent");
           const hasNameCollision =
             (nameCounts.get(suggestion.displayName.toLowerCase()) ?? 0) > 1;
           const collisionNpub =
@@ -160,7 +162,9 @@ export const MentionAutocomplete = React.memo(function MentionAutocomplete({
                     {suggestion.kind === "team" ? (
                       <span className="inline-flex shrink-0 items-center gap-1">
                         <Users aria-hidden="true" className="h-3.5 w-3.5" />
-                        team · {suggestion.teamMembers?.length ?? 0} agents
+                        {t("composer.mention.teamAgents", {
+                          count: suggestion.teamMembers?.length ?? 0,
+                        })}
                       </span>
                     ) : suggestion.isAgent ? (
                       <span className="inline-flex shrink-0 items-center gap-1">
@@ -184,17 +188,25 @@ export const MentionAutocomplete = React.memo(function MentionAutocomplete({
                         className="min-w-0 truncate"
                         title={
                           suggestion.ownerLabel && suggestion.notInChannel
-                            ? `managed by ${suggestion.ownerLabel} · not in channel`
+                            ? t("composer.mention.managedByNotInChannel", {
+                                owner: suggestion.ownerLabel,
+                              })
                             : suggestion.ownerLabel
-                              ? `managed by ${suggestion.ownerLabel}`
-                              : "not in channel"
+                              ? t("composer.mention.managedBy", {
+                                  owner: suggestion.ownerLabel,
+                                })
+                              : t("composer.mention.notInChannel")
                         }
                       >
                         {suggestion.ownerLabel && suggestion.notInChannel
-                          ? `managed by ${suggestion.ownerLabel} · not in channel`
+                          ? t("composer.mention.managedByNotInChannel", {
+                              owner: suggestion.ownerLabel,
+                            })
                           : suggestion.ownerLabel
-                            ? `managed by ${suggestion.ownerLabel}`
-                            : "not in channel"}
+                            ? t("composer.mention.managedBy", {
+                                owner: suggestion.ownerLabel,
+                              })
+                            : t("composer.mention.notInChannel")}
                       </span>
                     ) : null}
                   </span>
diff --git a/desktop/src/features/messages/ui/MessageActionBar.tsx b/desktop/src/features/messages/ui/MessageActionBar.tsx
index 967e50f5d2..e9d78a09e4 100644
--- a/desktop/src/features/messages/ui/MessageActionBar.tsx
+++ b/desktop/src/features/messages/ui/MessageActionBar.tsx
@@ -14,6 +14,7 @@ import {
   Trash2,
 } from "lucide-react";
 import * as React from "react";
+import { useTranslation } from "react-i18next";
 
 import { buildMessageLink } from "@/features/messages/lib/messageLink";
 import { EmojiPicker } from "@/features/custom-emoji/ui/EmojiPicker";
@@ -82,6 +83,7 @@ function MoreActionsMenu({
   isFollowingThread?: boolean;
   isUnread?: boolean;
 }) {
+  const { t } = useTranslation();
   const [isDeleteDialogOpen, setIsDeleteDialogOpen] = React.useState(false);
   const [isReportDialogOpen, setIsReportDialogOpen] = React.useState(false);
   // Set true the moment the user picks "Edit message". The
@@ -112,7 +114,7 @@ function MoreActionsMenu({
           <TooltipTrigger asChild>
             <DropdownMenuTrigger asChild>
               <Button
-                aria-label="More actions"
+                aria-label={t("composer.actions.more")}
                 className={ACTION_BUTTON_CLASS}
                 data-testid={`more-actions-${message.id}`}
                 size="sm"
@@ -123,7 +125,7 @@ function MoreActionsMenu({
               </Button>
             </DropdownMenuTrigger>
           </TooltipTrigger>
-          <TooltipContent>More actions</TooltipContent>
+          <TooltipContent>{t("composer.actions.more")}</TooltipContent>
         </Tooltip>
         <DropdownMenuContent
           align="end"
@@ -145,7 +147,7 @@ function MoreActionsMenu({
               }}
             >
               <Pencil className="h-4 w-4" />
-              Edit message
+              {t("composer.actions.edit")}
             </DropdownMenuItem>
           ) : null}
 
@@ -165,7 +167,9 @@ function MoreActionsMenu({
               ) : (
                 <MailOpen className="h-4 w-4" />
               )}
-              {isUnread ? "Mark read" : "Mark unread"}
+              {isUnread
+                ? t("composer.actions.markRead")
+                : t("composer.actions.markUnread")}
             </DropdownMenuItem>
           ) : null}
 
@@ -184,7 +188,9 @@ function MoreActionsMenu({
               ) : (
                 <BellRing className="h-4 w-4" />
               )}
-              {isFollowingThread ? "Unfollow thread" : "Follow thread"}
+              {isFollowingThread
+                ? t("composer.actions.unfollowThread")
+                : t("composer.actions.followThread")}
             </DropdownMenuItem>
           ) : null}
 
@@ -193,12 +199,12 @@ function MoreActionsMenu({
               onClick={() => {
                 copyTextToClipboard(
                   message.body,
-                  "Message copied to clipboard",
+                  t("composer.actions.messageCopied"),
                 );
               }}
             >
               <Copy className="h-4 w-4" />
-              Copy message
+              {t("composer.actions.copyMessage")}
             </DropdownMenuItem>
           ) : null}
 
@@ -209,7 +215,7 @@ function MoreActionsMenu({
               }}
             >
               <Clock className="h-4 w-4" />
-              Remind me later
+              {t("composer.actions.remindLater")}
             </DropdownMenuItem>
           ) : null}
 
@@ -223,11 +229,11 @@ function MoreActionsMenu({
                   messageId: message.id,
                   threadRootId: rootId,
                 });
-                copyTextToClipboard(link, "Link copied to clipboard");
+                copyTextToClipboard(link, t("composer.actions.linkCopied"));
               }}
             >
               <Link2 className="h-4 w-4" />
-              Copy link
+              {t("composer.actions.copyLink")}
             </DropdownMenuItem>
           ) : null}
 
@@ -241,7 +247,7 @@ function MoreActionsMenu({
               }}
             >
               <Flag className="h-4 w-4" />
-              Report message
+              {t("composer.actions.report")}
             </DropdownMenuItem>
           ) : null}
 
@@ -254,7 +260,7 @@ function MoreActionsMenu({
               }}
             >
               <Trash2 className="h-4 w-4" />
-              Delete message
+              {t("composer.actions.delete")}
             </DropdownMenuItem>
           ) : null}
 
@@ -371,6 +377,7 @@ export const MessageActionBar = React.memo(function MessageActionBar({
    *  unread badge uses. Drives the single mark-read/unread toggle label. */
   isUnread?: boolean;
 }) {
+  const { t } = useTranslation();
   const [isReactionPickerOpen, setIsReactionPickerOpen] = React.useState(false);
   const [isDropdownOpen, setIsDropdownOpen] = React.useState(false);
   const customEmoji = useCustomEmoji();
@@ -475,7 +482,7 @@ export const MessageActionBar = React.memo(function MessageActionBar({
                 <TooltipTrigger asChild>
                   <PopoverTrigger asChild>
                     <Button
-                      aria-label="Open reactions"
+                      aria-label={t("composer.actions.openReactions")}
                       className={ACTION_BUTTON_CLASS}
                       data-testid={`react-message-${message.id}`}
                       size="sm"
@@ -486,7 +493,7 @@ export const MessageActionBar = React.memo(function MessageActionBar({
                     </Button>
                   </PopoverTrigger>
                 </TooltipTrigger>
-                <TooltipContent>React</TooltipContent>
+                <TooltipContent>{t("composer.actions.react")}</TooltipContent>
               </Tooltip>
               <PopoverContent
                 align="end"
@@ -517,7 +524,7 @@ export const MessageActionBar = React.memo(function MessageActionBar({
             <Tooltip>
               <TooltipTrigger asChild>
                 <Button
-                  aria-label="Reply"
+                  aria-label={t("composer.actions.reply")}
                   className={ACTION_BUTTON_CLASS}
                   data-testid={`reply-message-${message.id}`}
                   onClick={() => {
@@ -530,7 +537,7 @@ export const MessageActionBar = React.memo(function MessageActionBar({
                   <CornerUpLeft className={ACTION_ICON_CLASS} />
                 </Button>
               </TooltipTrigger>
-              <TooltipContent>Reply</TooltipContent>
+              <TooltipContent>{t("composer.actions.reply")}</TooltipContent>
             </Tooltip>
           ) : null}
 
diff --git a/desktop/src/features/messages/ui/MessageComposerToolbar.tsx b/desktop/src/features/messages/ui/MessageComposerToolbar.tsx
index efb0d3b3b9..bfc46b1d0a 100644
--- a/desktop/src/features/messages/ui/MessageComposerToolbar.tsx
+++ b/desktop/src/features/messages/ui/MessageComposerToolbar.tsx
@@ -2,6 +2,7 @@ import * as React from "react";
 import type { Editor } from "@tiptap/react";
 import { AnimatePresence, motion } from "motion/react";
 import { ALargeSmall, ArrowUp, AtSign, Paperclip, X } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import { Button } from "@/shared/ui/button";
 import { Tooltip, TooltipContent, TooltipTrigger } from "@/shared/ui/tooltip";
@@ -52,6 +53,7 @@ export const MessageComposerToolbar = React.memo(
     onPaperclip: () => void;
     sendDisabled: boolean;
   }) {
+    const { t } = useTranslation();
     return (
       <div className="mt-2 flex flex-wrap items-center justify-between gap-3">
         <SelectionFormattingTray
@@ -91,7 +93,7 @@ export const MessageComposerToolbar = React.memo(
                   <Tooltip disableHoverableContent>
                     <TooltipTrigger asChild>
                       <Button
-                        aria-label="Toggle formatting"
+                        aria-label={t("composer.toolbar.toggleFormatting")}
                         aria-pressed={isFormattingOpen}
                         disabled={composerDisabled}
                         onClick={() => onFormattingToggle(!isFormattingOpen)}
@@ -103,7 +105,9 @@ export const MessageComposerToolbar = React.memo(
                         <ALargeSmall />
                       </Button>
                     </TooltipTrigger>
-                    <TooltipContent>Formatting</TooltipContent>
+                    <TooltipContent>
+                      {t("composer.toolbar.formatting")}
+                    </TooltipContent>
                   </Tooltip>
                 </motion.div>
                 <motion.div
@@ -116,7 +120,7 @@ export const MessageComposerToolbar = React.memo(
                   <Tooltip disableHoverableContent>
                     <TooltipTrigger asChild>
                       <Button
-                        aria-label="Close formatting"
+                        aria-label={t("composer.toolbar.closeFormatting")}
                         disabled={composerDisabled}
                         onClick={() => onFormattingToggle(false)}
                         onMouseDown={onCaptureSelection}
@@ -128,7 +132,9 @@ export const MessageComposerToolbar = React.memo(
                         <X />
                       </Button>
                     </TooltipTrigger>
-                    <TooltipContent>Close formatting</TooltipContent>
+                    <TooltipContent>
+                      {t("composer.toolbar.closeFormatting")}
+                    </TooltipContent>
                   </Tooltip>
                   <div className="mx-1 h-5 w-px shrink-0 bg-border/60" />
                 </motion.div>
@@ -162,7 +168,7 @@ export const MessageComposerToolbar = React.memo(
                 <Tooltip disableHoverableContent>
                   <TooltipTrigger asChild>
                     <Button
-                      aria-label="Mention someone"
+                      aria-label={t("composer.toolbar.mention")}
                       data-testid="message-insert-mention"
                       disabled={composerDisabled}
                       onClick={onOpenMentionPicker}
@@ -174,12 +180,14 @@ export const MessageComposerToolbar = React.memo(
                       <AtSign />
                     </Button>
                   </TooltipTrigger>
-                  <TooltipContent>Mention someone</TooltipContent>
+                  <TooltipContent>
+                    {t("composer.toolbar.mention")}
+                  </TooltipContent>
                 </Tooltip>
                 <Tooltip disableHoverableContent>
                   <TooltipTrigger asChild>
                     <Button
-                      aria-label="Attach file"
+                      aria-label={t("composer.toolbar.attachFile")}
                       disabled={composerDisabled || isUploading}
                       onClick={onPaperclip}
                       onMouseDown={onCaptureSelection}
@@ -190,7 +198,9 @@ export const MessageComposerToolbar = React.memo(
                       <Paperclip />
                     </Button>
                   </TooltipTrigger>
-                  <TooltipContent>Attach file</TooltipContent>
+                  <TooltipContent>
+                    {t("composer.toolbar.attachFile")}
+                  </TooltipContent>
                 </Tooltip>
                 <ComposerEmojiPicker
                   disabled={composerDisabled}
@@ -209,7 +219,7 @@ export const MessageComposerToolbar = React.memo(
                   <Tooltip disableHoverableContent>
                     <TooltipTrigger asChild>
                       <Button
-                        aria-label="Toggle formatting"
+                        aria-label={t("composer.toolbar.toggleFormatting")}
                         aria-pressed={isFormattingOpen}
                         disabled={composerDisabled}
                         onClick={() => onFormattingToggle(!isFormattingOpen)}
@@ -221,7 +231,9 @@ export const MessageComposerToolbar = React.memo(
                         <ALargeSmall />
                       </Button>
                     </TooltipTrigger>
-                    <TooltipContent>Formatting</TooltipContent>
+                    <TooltipContent>
+                      {t("composer.toolbar.formatting")}
+                    </TooltipContent>
                   </Tooltip>
                 </motion.div>
               </motion.div>
@@ -232,7 +244,11 @@ export const MessageComposerToolbar = React.memo(
         <div className="flex items-center gap-2">
           {extraActions}
           <Button
-            aria-label={isSending ? "Sending" : "Send message"}
+            aria-label={
+              isSending
+                ? t("composer.toolbar.sending")
+                : t("composer.toolbar.sendMessage")
+            }
             className="rounded-full"
             data-testid="send-message"
             disabled={sendDisabled || isSending}
diff --git a/desktop/src/features/settings/ui/LanguageSetting.tsx b/desktop/src/features/settings/ui/LanguageSetting.tsx
new file mode 100644
index 0000000000..5f99eba932
--- /dev/null
+++ b/desktop/src/features/settings/ui/LanguageSetting.tsx
@@ -0,0 +1,40 @@
+import { useTranslation } from "react-i18next";
+
+import { isAppLanguage, resolveAppLanguage, setAppLanguage } from "@/i18n";
+import { SettingsOptionGroup, SettingsOptionRow } from "./SettingsOptionGroup";
+
+export function LanguageSetting() {
+  const { i18n, t } = useTranslation();
+  const language = resolveAppLanguage(i18n.resolvedLanguage);
+
+  return (
+    <SettingsOptionGroup className="mt-8">
+      <SettingsOptionRow>
+        <div className="min-w-0">
+          <label className="text-sm font-medium" htmlFor="app-language">
+            {t("settings.language.label")}
+          </label>
+          <p className="text-sm font-normal text-muted-foreground">
+            {t("settings.language.description")}
+          </p>
+        </div>
+        <select
+          className="h-8 min-w-36 rounded-full border border-border/50 bg-muted/45 px-3 text-xs font-medium text-foreground outline-none focus-visible:ring-2 focus-visible:ring-ring"
+          data-testid="app-language"
+          id="app-language"
+          onChange={(event) => {
+            const nextLanguage = event.currentTarget.value;
+            if (isAppLanguage(nextLanguage)) {
+              void setAppLanguage(nextLanguage);
+            }
+          }}
+          value={language}
+        >
+          <option value="en">{t("settings.language.english")}</option>
+          <option value="zh-Hant">繁體中文</option>
+          <option value="zh-Hans">简体中文</option>
+        </select>
+      </SettingsOptionRow>
+    </SettingsOptionGroup>
+  );
+}
diff --git a/desktop/src/features/settings/ui/SettingsPanels.tsx b/desktop/src/features/settings/ui/SettingsPanels.tsx
index 901c9152b7..a0a3ad99cf 100644
--- a/desktop/src/features/settings/ui/SettingsPanels.tsx
+++ b/desktop/src/features/settings/ui/SettingsPanels.tsx
@@ -1,4 +1,5 @@
 import { useMemo, useState } from "react";
+import { useTranslation } from "react-i18next";
 import { AnimatePresence, motion, useReducedMotion } from "motion/react";
 import {
   Archive,
@@ -89,6 +90,7 @@ import { ProfileSettingsCard } from "./ProfileSettingsCard";
 import { UpdateChecker } from "../UpdateChecker";
 import { SettingsSectionHeader } from "./SettingsSectionHeader";
 import { VoiceSettingsCard } from "./VoiceSettingsCard";
+import { LanguageSetting } from "./LanguageSetting";
 
 export type SettingsSection =
   | "profile"
@@ -138,7 +140,7 @@ export function isSettingsSection(value: unknown): value is SettingsSection {
 
 export type SettingsSectionDescriptor = {
   value: SettingsSection;
-  label: string;
+  labelKey: string;
   icon: LucideIcon;
   /** If set, this section is only visible when the feature is enabled */
   featureGate?: string;
@@ -162,17 +164,17 @@ export type SettingsPanelProps = {
 export const settingsSections: SettingsSectionDescriptor[] = [
   {
     value: "appearance",
-    label: "Appearance",
+    labelKey: "settings.nav.sections.appearance",
     icon: MonitorCog,
   },
   {
     value: "profile",
-    label: "Profile",
+    labelKey: "settings.nav.sections.profile",
     icon: UserRound,
   },
   {
     value: "notifications",
-    label: "Notifications",
+    labelKey: "settings.nav.sections.notifications",
     icon: BellRing,
   },
   {
@@ -182,65 +184,65 @@ export const settingsSections: SettingsSectionDescriptor[] = [
   },
   {
     value: "experimental",
-    label: "Experiments",
+    labelKey: "settings.nav.sections.experimental",
     icon: FlaskConical,
   },
   {
     value: "agents",
-    label: "Agents",
+    labelKey: "settings.nav.sections.agents",
     icon: Bot,
     featureGate: "managed-agents",
   },
   {
     value: "channel-templates",
-    label: "Channel templates",
+    labelKey: "settings.nav.sections.channelTemplates",
     icon: LayoutTemplate,
     featureGate: "channel-templates",
   },
   {
     value: "compute",
-    label: "Compute",
+    labelKey: "settings.nav.sections.compute",
     icon: Cpu,
   },
   {
     value: "shortcuts",
-    label: "Shortcuts",
+    labelKey: "settings.nav.sections.shortcuts",
     icon: Keyboard,
   },
   {
     value: "hosted-communities",
-    label: "Hosted communities",
+    labelKey: "settings.nav.sections.hostedCommunities",
     icon: MessagesSquare,
   },
   {
     value: "community-members",
-    label: "Invites",
+    labelKey: "settings.nav.sections.communityMembers",
     icon: Ticket,
   },
   {
     value: "moderation",
-    label: "Moderation",
+    labelKey: "settings.nav.sections.moderation",
     icon: ShieldAlert,
   },
   {
     value: "custom-emoji",
-    label: "Custom emoji",
+    labelKey: "settings.nav.sections.customEmoji",
     icon: Smile,
     featureGate: "custom-emoji",
   },
   {
     value: "local-archive",
-    label: "Local archive",
+    labelKey: "settings.nav.sections.localArchive",
     icon: Archive,
   },
   {
     value: "mobile",
-    label: "Mobile",
+    labelKey: "settings.nav.sections.mobile",
     icon: Smartphone,
   },
   {
     value: "updates",
-    label: "Updates",
+    labelKey: "settings.nav.sections.updates",
     icon: Download,
   },
 ];
@@ -422,6 +424,7 @@ const ACCENT_PICKER_TRANSITION = {
 };
 
 function ThemeSettingsCard() {
+  const { t } = useTranslation();
   const {
     setTheme,
     selectedThemeName,
@@ -536,8 +539,8 @@ function ThemeSettingsCard() {
       data-testid="settings-theme"
     >
       <SettingsSectionHeader
-        title="Appearance"
-        description="Choose a theme for Buzz."
+        title={t("settings.appearance.title")}
+        description={t("settings.appearance.description")}
       />
 
       {/* Mode, theme, and accent are saved per community
@@ -572,9 +575,21 @@ function ThemeSettingsCard() {
       <div className="mb-4 flex gap-2">
         {(
           [
-            { mode: "system" as const, label: "System", Icon: SunMoon },
-            { mode: "light" as const, label: "Light", Icon: Sun },
-            { mode: "dark" as const, label: "Dark", Icon: Moon },
+            {
+              mode: "system" as const,
+              label: t("settings.appearance.system"),
+              Icon: SunMoon,
+            },
+            {
+              mode: "light" as const,
+              label: t("settings.appearance.light"),
+              Icon: Sun,
+            },
+            {
+              mode: "dark" as const,
+              label: t("settings.appearance.dark"),
+              Icon: Moon,
+            },
           ] as const
         ).map(({ mode, label, Icon }) => (
           <button
@@ -695,24 +710,25 @@ function ThemeSettingsCard() {
       )}
 
       <ThreadLayoutSetting />
+      <LanguageSetting />
     </section>
   );
 }
 
 const THREAD_VIEW_MODE_OPTIONS: {
   value: ThreadViewMode;
-  label: string;
-  description: string;
+  labelKey: string;
+  descriptionKey: string;
 }[] = [
   {
     value: "focus",
-    label: "Focus",
-    description: "Threads open over the channel, full width",
+    labelKey: "settings.appearance.threadFocus",
+    descriptionKey: "settings.appearance.threadFocusDescription",
   },
   {
     value: "split",
-    label: "Split",
-    description: "Threads open in a side panel next to the channel",
+    labelKey: "settings.appearance.threadSplit",
+    descriptionKey: "settings.appearance.threadSplitDescription",
   },
 ];
 
@@ -722,6 +738,7 @@ const THREAD_VIEW_MODE_OPTIONS: {
  * carry its own description.
  */
 function ThreadLayoutSetting() {
+  const { t } = useTranslation();
   const threadViewMode = useThreadViewMode();
   // The "(all communities)" qualifier contrasts with the per-community theme
   // controls above; it's only meaningful when the user has multiple
@@ -738,7 +755,7 @@ function ThreadLayoutSetting() {
       <SettingsOptionRow>
         <div className="min-w-0">
           <p className="text-sm font-medium">
-            Thread layout
+            {t("settings.appearance.threadLayout")}
             {showCommunityScope ? (
               <span className="font-normal text-muted-foreground">
                 {" "}
@@ -747,7 +764,7 @@ function ThreadLayoutSetting() {
             ) : null}
           </p>
           <p className="text-sm font-normal text-muted-foreground">
-            {activeOption.description}
+            {t(activeOption.descriptionKey)}
           </p>
         </div>
         <DropdownMenu modal={false}>
@@ -759,7 +776,7 @@ function ThreadLayoutSetting() {
               type="button"
               variant="ghost"
             >
-              <span className="truncate">{activeOption.label}</span>
+              <span className="truncate">{t(activeOption.labelKey)}</span>
               <ChevronDown className="h-4 w-4 text-muted-foreground" />
             </Button>
           </DropdownMenuTrigger>
@@ -777,9 +794,9 @@ function ThreadLayoutSetting() {
                   value={option.value}
                 >
                   <span className="flex min-w-0 flex-col">
-                    <span className="font-medium">{option.label}</span>
+                    <span className="font-medium">{t(option.labelKey)}</span>
                     <span className="text-2xs text-muted-foreground">
-                      {option.description}
+                      {t(option.descriptionKey)}
                     </span>
                   </span>
                 </DropdownMenuRadioItem>
@@ -802,9 +819,12 @@ function AccentPickerContent({
   isDark: boolean;
   setAccentColor: (value: string) => void;
 }) {
+  const { t } = useTranslation();
   return (
     <div className="shrink-0 px-1 pb-2 pt-1">
-      <h3 className="mb-2 text-sm font-medium">Accent color</h3>
+      <h3 className="mb-2 text-sm font-medium">
+        {t("settings.appearance.accentColor")}
+      </h3>
       <div className="flex flex-wrap gap-2 p-1">
         {ACCENT_COLORS.map((color) => {
           const isNeutral = color.value === NEUTRAL_ACCENT;
diff --git a/desktop/src/features/settings/ui/SettingsView.tsx b/desktop/src/features/settings/ui/SettingsView.tsx
index 991029dca7..6d6dc2b1c3 100644
--- a/desktop/src/features/settings/ui/SettingsView.tsx
+++ b/desktop/src/features/settings/ui/SettingsView.tsx
@@ -1,6 +1,7 @@
 import * as React from "react";
 import { getVersion } from "@tauri-apps/api/app";
 import { AlertCircle, ArrowLeft, LoaderCircle, RefreshCw } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import { useMyRelayMembershipLookupQuery } from "@/features/community-members/hooks";
 import {
@@ -49,11 +50,11 @@ type SettingsViewProps = SettingsPanelProps & {
 };
 
 const settingsNavGroups: Array<{
-  label: string;
+  labelKey: string;
   sections: SettingsSection[];
 }> = [
   {
-    label: "Personal",
+    labelKey: "settings.nav.groups.personal",
     sections: [
       "profile",
       "appearance",
@@ -66,11 +67,11 @@ const settingsNavGroups: Array<{
     ],
   },
   {
-    label: "Communities",
+    labelKey: "settings.nav.groups.communities",
     sections: ["hosted-communities", "community-members"],
   },
   {
-    label: "App",
+    labelKey: "settings.nav.groups.app",
     sections: ["agents", "compute", "experimental", "mobile", "updates"],
   },
 ];
@@ -85,6 +86,8 @@ function SettingsSectionButton({
   section: (typeof settingsSections)[number];
 }) {
   const Icon = section.icon;
+  const { t } = useTranslation();
+  const label = t(section.labelKey);
 
   return (
     <SidebarMenuItem>
@@ -93,7 +96,7 @@ function SettingsSectionButton({
         data-testid={`settings-nav-${section.value}`}
         isActive={active}
         onClick={() => onSelect(section.value)}
-        tooltip={section.label}
+        tooltip={label}
         type="button"
       >
         <Icon
@@ -104,7 +107,7 @@ function SettingsSectionButton({
               : "text-sidebar-foreground/70",
           )}
         />
-        <SidebarMenuLabel>{section.label}</SidebarMenuLabel>
+        <SidebarMenuLabel>{label}</SidebarMenuLabel>
       </SidebarMenuButton>
     </SidebarMenuItem>
   );
@@ -127,6 +130,7 @@ export function SettingsView({
   onSetSoundForSlot,
   section,
 }: SettingsViewProps) {
+  const { t } = useTranslation();
   const { isMobile, open: sidebarOpen, setOpen: setSidebarOpen } = useSidebar();
   const myMembershipQuery = useMyRelayMembershipLookupQuery();
   const featureState = useFeatureSnapshot();
@@ -227,11 +231,11 @@ export function SettingsView({
               <SidebarMenuButton
                 data-testid="settings-back-to-app"
                 onClick={onClose}
-                tooltip="Back to app"
+                tooltip={t("settings.nav.backToApp")}
                 type="button"
               >
                 <ArrowLeft className="h-4 w-4" />
-                <span>Back to app</span>
+                <span>{t("settings.nav.backToApp")}</span>
               </SidebarMenuButton>
             </SidebarMenuItem>
           </SidebarMenu>
@@ -244,7 +248,7 @@ export function SettingsView({
               data-testid="community-access-loading"
             >
               <LoaderCircle className="h-3.5 w-3.5 animate-spin" />
-              Checking invite permissions…
+              {t("settings.access.checking")}
             </div>
           ) : null}
           {myMembershipQuery.isError ? (
@@ -254,7 +258,7 @@ export function SettingsView({
             >
               <div className="flex items-center gap-2">
                 <AlertCircle className="h-3.5 w-3.5 text-destructive" />
-                Invite settings could not be checked.
+                {t("settings.access.error")}
               </div>
               <button
                 className="flex items-center gap-1.5 font-medium text-sidebar-foreground underline-offset-2 hover:underline"
@@ -262,7 +266,7 @@ export function SettingsView({
                 type="button"
               >
                 <RefreshCw className="h-3.5 w-3.5" />
-                Try again
+                {t("settings.access.retry")}
               </button>
             </div>
           ) : null}
@@ -272,15 +276,18 @@ export function SettingsView({
               data-testid="community-access-snapshot-missing"
             >
               <AlertCircle className="mt-0.5 h-3.5 w-3.5 shrink-0 text-amber-500" />
-              Invite settings are unavailable. Relay recovery may still be in
-              progress.
+              {t("settings.access.unavailable")}
             </div>
           ) : null}
           {visibleNavGroups.map((group) => (
-            <SidebarGroup key={group.label}>
-              <SidebarGroupLabel>{group.label}</SidebarGroupLabel>
+            <SidebarGroup key={group.labelKey}>
+              <SidebarGroupLabel>{t(group.labelKey)}</SidebarGroupLabel>
               <SidebarGroupContent>
-                <SidebarMenu aria-label={`${group.label} settings sections`}>
+                <SidebarMenu
+                  aria-label={t("settings.nav.sectionsLabel", {
+                    group: t(group.labelKey),
+                  })}
+                >
                   {group.sections.map((entry) => (
                     <SettingsSectionButton
                       active={entry.value === section}
diff --git a/desktop/src/features/sidebar/ui/AppSidebarPinnedHeader.tsx b/desktop/src/features/sidebar/ui/AppSidebarPinnedHeader.tsx
index 14463060d4..547aedcb04 100644
--- a/desktop/src/features/sidebar/ui/AppSidebarPinnedHeader.tsx
+++ b/desktop/src/features/sidebar/ui/AppSidebarPinnedHeader.tsx
@@ -1,4 +1,5 @@
 import { Activity, Bot, FolderGit2, Inbox, Zap } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import { TopbarSearch } from "@/features/search/ui/TopbarSearch";
 import { FeatureGate } from "@/shared/features";
@@ -89,6 +90,7 @@ export function AppSidebarPrimaryMenu({
   onSelectWorkflows,
   selectedView,
 }: AppSidebarPrimaryMenuProps) {
+  const { t } = useTranslation();
   return (
     <SidebarHeader
       className="relative z-40 cursor-default select-none px-2 pb-0 pt-0"
@@ -101,7 +103,7 @@ export function AppSidebarPrimaryMenu({
             className="data-[active=true]:font-normal"
             isActive={selectedView === "home"}
             onClick={onSelectHome}
-            tooltip="Inbox"
+            tooltip={t("sidebar.primary.inbox")}
             type="button"
           >
             <Inbox
@@ -112,7 +114,7 @@ export function AppSidebarPrimaryMenu({
             <SidebarMenuLabel
               className={selectedView !== "home" ? "opacity-80" : undefined}
             >
-              Inbox
+              {t("sidebar.primary.inbox")}
             </SidebarMenuLabel>
           </SidebarMenuButton>
           {homeBadgeCount > 0 ? (
@@ -130,11 +132,11 @@ export function AppSidebarPrimaryMenu({
               data-testid="open-pulse-view"
               isActive={selectedView === "pulse"}
               onClick={onSelectPulse}
-              tooltip="Pulse"
+              tooltip={t("sidebar.primary.pulse")}
               type="button"
             >
               <Activity className="h-4 w-4" />
-              <SidebarMenuLabel>Pulse</SidebarMenuLabel>
+              <SidebarMenuLabel>{t("sidebar.primary.pulse")}</SidebarMenuLabel>
             </SidebarMenuButton>
           </SidebarMenuItem>
         </FeatureGate>
@@ -144,11 +146,13 @@ export function AppSidebarPrimaryMenu({
               data-testid="open-projects-view"
               isActive={selectedView === "projects"}
               onClick={onSelectProjects}
-              tooltip="Projects"
+              tooltip={t("sidebar.primary.projects")}
               type="button"
             >
               <FolderGit2 className="h-4 w-4" />
-              <SidebarMenuLabel>Projects</SidebarMenuLabel>
+              <SidebarMenuLabel>
+                {t("sidebar.primary.projects")}
+              </SidebarMenuLabel>
             </SidebarMenuButton>
           </SidebarMenuItem>
         </FeatureGate>
@@ -158,7 +162,7 @@ export function AppSidebarPrimaryMenu({
             data-testid="open-agents-view"
             isActive={selectedView === "agents"}
             onClick={onSelectAgents}
-            tooltip="Agents"
+            tooltip={t("sidebar.primary.agents")}
             type="button"
           >
             <Bot
@@ -169,7 +173,7 @@ export function AppSidebarPrimaryMenu({
             <SidebarMenuLabel
               className={selectedView !== "agents" ? "opacity-80" : undefined}
             >
-              Agents
+              {t("sidebar.primary.agents")}
             </SidebarMenuLabel>
           </SidebarMenuButton>
         </SidebarMenuItem>
@@ -179,11 +183,13 @@ export function AppSidebarPrimaryMenu({
               data-testid="open-workflows-view"
               isActive={selectedView === "workflows"}
               onClick={onSelectWorkflows}
-              tooltip="Workflows"
+              tooltip={t("sidebar.primary.workflows")}
               type="button"
             >
               <Zap className="h-4 w-4" />
-              <SidebarMenuLabel>Workflows</SidebarMenuLabel>
+              <SidebarMenuLabel>
+                {t("sidebar.primary.workflows")}
+              </SidebarMenuLabel>
             </SidebarMenuButton>
           </SidebarMenuItem>
         </FeatureGate>
diff --git a/desktop/src/features/sidebar/ui/ChannelContextMenu.tsx b/desktop/src/features/sidebar/ui/ChannelContextMenu.tsx
index 78f3929f19..2338ec6a6d 100644
--- a/desktop/src/features/sidebar/ui/ChannelContextMenu.tsx
+++ b/desktop/src/features/sidebar/ui/ChannelContextMenu.tsx
@@ -14,6 +14,7 @@ import {
   Trash2,
   TriangleAlert,
 } from "lucide-react";
+import { useTranslation } from "react-i18next";
 
 import { useAppShell } from "@/app/AppShellContext";
 import {
@@ -108,31 +109,29 @@ function MoveToSectionSubmenu({
  * "Copy" submenu (channel name / channel ID).
  */
 function CopyChannelSubmenu({ channel }: { channel: Channel }) {
+  const { t } = useTranslation();
   return (
     <ContextMenuSub>
       <ContextMenuSubTrigger>
         <ContextMenuIconSlot>
           <Copy className="h-4 w-4" />
         </ContextMenuIconSlot>
-        <span>Copy</span>
+        <span>{t("sidebar.channel.copy")}</span>
       </ContextMenuSubTrigger>
       <ContextMenuSubContent>
         <ContextMenuItem
           onSelect={() =>
-            copyTextToClipboard(
-              channel.name,
-              "Channel name copied to clipboard",
-            )
+            copyTextToClipboard(channel.name, t("sidebar.channel.nameCopied"))
           }
         >
-          <span>Copy channel name</span>
+          <span>{t("sidebar.channel.copyName")}</span>
         </ContextMenuItem>
         <ContextMenuItem
           onSelect={() =>
-            copyTextToClipboard(channel.id, "Channel ID copied to clipboard")
+            copyTextToClipboard(channel.id, t("sidebar.channel.idCopied"))
           }
         >
-          <span>Copy channel ID</span>
+          <span>{t("sidebar.channel.copyId")}</span>
         </ContextMenuItem>
       </ContextMenuSubContent>
     </ContextMenuSub>
@@ -179,6 +178,7 @@ export function ChannelContextMenuItems({
   onDeleteChannel?: (channel: Channel) => void;
   onLeaveChannel?: (channel: Channel) => void;
 }) {
+  const { t } = useTranslation();
   const {
     feedItemState,
     hasSidebarUnreadProjections,
@@ -261,7 +261,7 @@ export function ChannelContextMenuItems({
           <ContextMenuIconSlot>
             <CheckCircle2 className="h-4 w-4" />
           </ContextMenuIconSlot>
-          <span>Mark as read</span>
+          <span>{t("sidebar.channel.markAsRead")}</span>
         </ContextMenuItem>
       ) : !hasProjectedUnread && onMarkChannelUnread ? (
         <ContextMenuItem
@@ -272,7 +272,7 @@ export function ChannelContextMenuItems({
           <ContextMenuIconSlot>
             <CircleDot className="h-4 w-4" />
           </ContextMenuIconSlot>
-          <span>Mark unread</span>
+          <span>{t("sidebar.channel.markUnread")}</span>
         </ContextMenuItem>
       ) : null}
       {showMuteToggle || showStar ? <ContextMenuSeparator /> : null}
@@ -286,7 +286,7 @@ export function ChannelContextMenuItems({
             <ContextMenuIconSlot>
               <Bell className="h-4 w-4" />
             </ContextMenuIconSlot>
-            <span>Unmute channel</span>
+            <span>{t("sidebar.channel.unmute")}</span>
           </ContextMenuItem>
         ) : (
           <ContextMenuItem
@@ -295,7 +295,7 @@ export function ChannelContextMenuItems({
             <ContextMenuIconSlot>
               <BellOff className="h-4 w-4" />
             </ContextMenuIconSlot>
-            <span>Mute channel</span>
+            <span>{t("sidebar.channel.mute")}</span>
           </ContextMenuItem>
         )
       ) : null}
@@ -309,7 +309,7 @@ export function ChannelContextMenuItems({
             <ContextMenuIconSlot>
               <StarOff className="h-4 w-4" />
             </ContextMenuIconSlot>
-            <span>Unstar channel</span>
+            <span>{t("sidebar.channel.unstar")}</span>
           </ContextMenuItem>
         ) : (
           <ContextMenuItem
@@ -318,7 +318,7 @@ export function ChannelContextMenuItems({
             <ContextMenuIconSlot>
               <Star className="h-4 w-4" />
             </ContextMenuIconSlot>
-            <span>Star channel</span>
+            <span>{t("sidebar.channel.star")}</span>
           </ContextMenuItem>
         )
       ) : null}
@@ -331,7 +331,7 @@ export function ChannelContextMenuItems({
           <ContextMenuIconSlot>
             <LogOut className="h-4 w-4" />
           </ContextMenuIconSlot>
-          <span>Leave channel</span>
+          <span>{t("sidebar.channel.leave")}</span>
         </ContextMenuItem>
       ) : null}
       {ownerActionsLoading ? (
@@ -358,7 +358,7 @@ export function ChannelContextMenuItems({
           <ContextMenuIconSlot>
             <Archive className="h-4 w-4" />
           </ContextMenuIconSlot>
-          <span>Archive channel</span>
+          <span>{t("sidebar.channel.archive")}</span>
         </ContextMenuItem>
       ) : null}
       {canDeleteChannel ? (
@@ -370,7 +370,7 @@ export function ChannelContextMenuItems({
           <ContextMenuIconSlot>
             <Trash2 className="h-4 w-4" />
           </ContextMenuIconSlot>
-          <span>Delete channel</span>
+          <span>{t("sidebar.channel.delete")}</span>
         </ContextMenuItem>
       ) : null}
     </>
diff --git a/desktop/src/features/sidebar/ui/SidebarSection.tsx b/desktop/src/features/sidebar/ui/SidebarSection.tsx
index 56e12146b9..2622dc3daf 100644
--- a/desktop/src/features/sidebar/ui/SidebarSection.tsx
+++ b/desktop/src/features/sidebar/ui/SidebarSection.tsx
@@ -1,4 +1,5 @@
 import type * as React from "react";
+import { useTranslation } from "react-i18next";
 import {
   BellOff,
   ChevronDown,
@@ -70,6 +71,7 @@ function UnreadCountBadge({
   className?: string;
   count: number;
 }) {
+  const { t } = useTranslation();
   return (
     <span
       className={cn(
@@ -79,7 +81,10 @@ function UnreadCountBadge({
       data-testid={`channel-unread-${channelName}`}
     >
       {formatUnreadCount(count)}
-      <span className="sr-only"> new comment{count === 1 ? "" : "s"}</span>
+      <span className="sr-only">
+        {" "}
+        {t("sidebar.channel.newComments", { count })}
+      </span>
     </span>
   );
 }
@@ -91,12 +96,13 @@ function UnreadDotBadge({
   channelName: string;
   className?: string;
 }) {
+  const { t } = useTranslation();
   return (
     <span
       className={cn("h-2 w-2 shrink-0 rounded-full bg-primary", className)}
       data-testid={`channel-unread-dot-${channelName}`}
     >
-      <span className="sr-only">unread</span>
+      <span className="sr-only">{t("sidebar.channel.unread")}</span>
     </span>
   );
 }
@@ -423,6 +429,7 @@ export function SidebarSection({
   onUnmuteChannel?: (channelId: string) => void;
   sectionActionsOpen?: boolean;
 }) {
+  const { t } = useTranslation();
   if (items.length === 0 && !action && !emptyState) {
     return null;
   }
@@ -503,7 +510,7 @@ export function SidebarSection({
                     ) : null}
                     {channel.channelType === "dm" && onHideDm ? (
                       <button
-                        aria-label="Close direct message"
+                        aria-label={t("sidebar.channel.closeDirectMessage")}
                         className={cn(
                           "absolute right-1 top-1/2 z-10 -translate-y-1/2 after:absolute after:-inset-2 after:md:hidden group-data-[collapsible=icon]:hidden",
                           SIDEBAR_ROW_ICON_ACTION_CLASS,
diff --git a/desktop/src/i18n.test.mjs b/desktop/src/i18n.test.mjs
new file mode 100644
index 0000000000..c8cdf90344
--- /dev/null
+++ b/desktop/src/i18n.test.mjs
@@ -0,0 +1,58 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import { createAppI18n } from "./i18n.ts";
+
+test("changing language updates translated text without a restart", async () => {
+  const instance = createAppI18n(
+    {
+      en: {
+        translation: {
+          sample: "English sample",
+        },
+      },
+      "zh-Hant": {
+        translation: {
+          sample: "Localized sample",
+        },
+      },
+      "zh-Hans": {
+        translation: {
+          sample: "Another localized sample",
+        },
+      },
+    },
+    "en",
+  );
+
+  assert.equal(instance.t("sample"), "English sample");
+
+  await instance.changeLanguage("zh-Hant");
+
+  assert.equal(instance.t("sample"), "Localized sample");
+});
+
+test("empty Chinese values fall back to English", async () => {
+  const instance = createAppI18n(
+    {
+      en: {
+        translation: {
+          sample: "English fallback",
+        },
+      },
+      "zh-Hant": {
+        translation: {
+          sample: "",
+        },
+      },
+      "zh-Hans": {
+        translation: {
+          sample: "",
+        },
+      },
+    },
+    "zh-Hant",
+  );
+
+  assert.equal(instance.t("sample"), "English fallback");
+});
diff --git a/desktop/src/i18n.ts b/desktop/src/i18n.ts
new file mode 100644
index 0000000000..f573c3f2ee
--- /dev/null
+++ b/desktop/src/i18n.ts
@@ -0,0 +1,77 @@
+import {
+  createInstance,
+  type i18n as I18nInstance,
+  type Resource,
+} from "i18next";
+import { initReactI18next } from "react-i18next";
+
+import en from "@/locales/en.json";
+import zhHans from "@/locales/zh-Hans.json";
+import zhHant from "@/locales/zh-Hant.json";
+
+export const APP_LANGUAGES = ["en", "zh-Hant", "zh-Hans"] as const;
+export type AppLanguage = (typeof APP_LANGUAGES)[number];
+
+export const DEFAULT_LANGUAGE: AppLanguage = "en";
+export const LANGUAGE_STORAGE_KEY = "buzz-language";
+
+export function isAppLanguage(value: unknown): value is AppLanguage {
+  return (
+    typeof value === "string" &&
+    (APP_LANGUAGES as readonly string[]).includes(value)
+  );
+}
+
+export function resolveAppLanguage(value: unknown): AppLanguage {
+  return isAppLanguage(value) ? value : DEFAULT_LANGUAGE;
+}
+
+function readStoredLanguage(): AppLanguage {
+  if (typeof window === "undefined") return DEFAULT_LANGUAGE;
+  return resolveAppLanguage(window.localStorage.getItem(LANGUAGE_STORAGE_KEY));
+}
+
+export function createAppI18n(
+  resources: Resource,
+  language: AppLanguage,
+): I18nInstance {
+  const instance = createInstance();
+  void instance.use(initReactI18next).init({
+    resources,
+    lng: language,
+    fallbackLng: DEFAULT_LANGUAGE,
+    supportedLngs: APP_LANGUAGES,
+    load: "currentOnly",
+    returnEmptyString: false,
+    initAsync: false,
+    interpolation: {
+      escapeValue: false,
+    },
+  });
+  return instance;
+}
+
+export const i18n = createAppI18n(
+  {
+    en: { translation: en },
+    "zh-Hant": { translation: zhHant },
+    "zh-Hans": { translation: zhHans },
+  },
+  readStoredLanguage(),
+);
+
+function applyDocumentLanguage(language: AppLanguage) {
+  if (typeof document !== "undefined") {
+    document.documentElement.lang = language;
+  }
+}
+
+applyDocumentLanguage(resolveAppLanguage(i18n.resolvedLanguage));
+
+export async function setAppLanguage(language: AppLanguage): Promise<void> {
+  if (typeof window !== "undefined") {
+    window.localStorage.setItem(LANGUAGE_STORAGE_KEY, language);
+  }
+  await i18n.changeLanguage(language);
+  applyDocumentLanguage(language);
+}
diff --git a/desktop/src/locales/STRINGS-MANIFEST.md b/desktop/src/locales/STRINGS-MANIFEST.md
new file mode 100644
index 0000000000..c552b5b904
--- /dev/null
+++ b/desktop/src/locales/STRINGS-MANIFEST.md
@@ -0,0 +1,148 @@
+# Desktop i18n strings manifest
+
+This v1 manifest contains the English source strings extracted from the bounded Settings, main sidebar, message composer/actions, and Agents surfaces. The two Chinese locale scaffolds intentionally contain empty values so the app falls back to English until native-quality translations are supplied.
+
+| Key | English source | UI context |
+| --- | --- | --- |
+| `settings.nav.backToApp` | Back to app | Settings sidebar navigation |
+| `settings.nav.groups.personal` | Personal | Settings sidebar navigation group |
+| `settings.nav.groups.communities` | Communities | Settings sidebar navigation group |
+| `settings.nav.groups.app` | App | Settings sidebar navigation group |
+| `settings.nav.sectionsLabel` | {{group}} settings sections | Settings sidebar navigation |
+| `settings.nav.sections.appearance` | Appearance | Settings sidebar section label |
+| `settings.nav.sections.profile` | Profile | Settings sidebar section label |
+| `settings.nav.sections.notifications` | Notifications | Settings sidebar section label |
+| `settings.nav.sections.experimental` | Experiments | Settings sidebar section label |
+| `settings.nav.sections.agents` | Agents | Settings sidebar section label |
+| `settings.nav.sections.channelTemplates` | Channel templates | Settings sidebar section label |
+| `settings.nav.sections.compute` | Compute | Settings sidebar section label |
+| `settings.nav.sections.shortcuts` | Shortcuts | Settings sidebar section label |
+| `settings.nav.sections.hostedCommunities` | Hosted communities | Settings sidebar section label |
+| `settings.nav.sections.communityMembers` | Invites | Settings sidebar section label |
+| `settings.nav.sections.moderation` | Moderation | Settings sidebar section label |
+| `settings.nav.sections.customEmoji` | Custom emoji | Settings sidebar section label |
+| `settings.nav.sections.localArchive` | Local archive | Settings sidebar section label |
+| `settings.nav.sections.mobile` | Mobile | Settings sidebar section label |
+| `settings.nav.sections.updates` | Updates | Settings sidebar section label |
+| `settings.access.checking` | Checking invite permissions… | Settings sidebar invite-permission status |
+| `settings.access.error` | Invite settings could not be checked. | Settings sidebar invite-permission status |
+| `settings.access.retry` | Try again | Settings sidebar invite-permission status |
+| `settings.access.unavailable` | Invite settings are unavailable. Relay recovery may still be in progress. | Settings sidebar invite-permission status |
+| `settings.appearance.title` | Appearance | Appearance settings panel |
+| `settings.appearance.description` | Choose a theme for Buzz. | Appearance settings panel |
+| `settings.appearance.system` | System | Appearance settings panel |
+| `settings.appearance.light` | Light | Appearance settings panel |
+| `settings.appearance.dark` | Dark | Appearance settings panel |
+| `settings.appearance.accentColor` | Accent color | Appearance settings panel |
+| `settings.appearance.threadLayout` | Thread layout | Appearance settings panel |
+| `settings.appearance.threadFocus` | Focus | Appearance settings panel |
+| `settings.appearance.threadFocusDescription` | Threads open over the channel, full width | Appearance settings panel |
+| `settings.appearance.threadSplit` | Split | Appearance settings panel |
+| `settings.appearance.threadSplitDescription` | Threads open in a side panel next to the channel | Appearance settings panel |
+| `settings.language.label` | Language | Language selector row in Appearance settings |
+| `settings.language.description` | Choose the language used by Buzz. | Language selector row in Appearance settings |
+| `settings.language.english` | English | Language selector row in Appearance settings |
+| `sidebar.primary.inbox` | Inbox | Main app sidebar primary navigation |
+| `sidebar.primary.pulse` | Pulse | Main app sidebar primary navigation |
+| `sidebar.primary.projects` | Projects | Main app sidebar primary navigation |
+| `sidebar.primary.agents` | Agents | Main app sidebar primary navigation |
+| `sidebar.primary.workflows` | Workflows | Main app sidebar primary navigation |
+| `sidebar.community.notConnected` | Not connected | Community switcher and community action menu |
+| `sidebar.community.connecting` | Connecting… | Community switcher and community action menu |
+| `sidebar.community.connected` | Connected | Community switcher and community action menu |
+| `sidebar.community.reconnecting` | Reconnecting to relay… | Community switcher and community action menu |
+| `sidebar.community.stalled` | Connection lost — relay is not responding | Community switcher and community action menu |
+| `sidebar.community.disconnected` | Disconnected from relay | Community switcher and community action menu |
+| `sidebar.community.noCommunity` | No community | Community switcher and community action menu |
+| `sidebar.community.community` | Community | Community switcher and community action menu |
+| `sidebar.community.actions` | Community actions | Community switcher and community action menu |
+| `sidebar.community.copyUrl` | Copy community URL | Community switcher and community action menu |
+| `sidebar.community.invite` | Invite to community | Community switcher and community action menu |
+| `sidebar.community.settings` | Community settings | Community switcher and community action menu |
+| `sidebar.community.add` | Add a community | Community switcher and community action menu |
+| `sidebar.community.switch` | Switch community | Community switcher and community action menu |
+| `sidebar.community.edit` | Edit {{name}} | Community switcher and community action menu |
+| `sidebar.channel.closeDirectMessage` | Close direct message | Channel row and channel context menu |
+| `sidebar.channel.newComments_one` | new comment | Channel row and channel context menu |
+| `sidebar.channel.newComments_other` | new comments | Channel row and channel context menu |
+| `sidebar.channel.unread` | unread | Channel row and channel context menu |
+| `sidebar.channel.copy` | Copy | Channel row and channel context menu |
+| `sidebar.channel.copyName` | Copy channel name | Channel row and channel context menu |
+| `sidebar.channel.copyId` | Copy channel ID | Channel row and channel context menu |
+| `sidebar.channel.nameCopied` | Channel name copied to clipboard | Channel row and channel context menu |
+| `sidebar.channel.idCopied` | Channel ID copied to clipboard | Channel row and channel context menu |
+| `sidebar.channel.markAsRead` | Mark as read | Channel row and channel context menu |
+| `sidebar.channel.markUnread` | Mark unread | Channel row and channel context menu |
+| `sidebar.channel.mute` | Mute channel | Channel row and channel context menu |
+| `sidebar.channel.unmute` | Unmute channel | Channel row and channel context menu |
+| `sidebar.channel.star` | Star channel | Channel row and channel context menu |
+| `sidebar.channel.unstar` | Unstar channel | Channel row and channel context menu |
+| `sidebar.channel.leave` | Leave channel | Channel row and channel context menu |
+| `sidebar.channel.archive` | Archive channel | Channel row and channel context menu |
+| `sidebar.channel.delete` | Delete channel | Channel row and channel context menu |
+| `composer.toolbar.formatting` | Formatting | Message composer action toolbar |
+| `composer.toolbar.toggleFormatting` | Toggle formatting | Message composer action toolbar |
+| `composer.toolbar.closeFormatting` | Close formatting | Message composer action toolbar |
+| `composer.toolbar.mention` | Mention someone | Message composer action toolbar |
+| `composer.toolbar.attachFile` | Attach file | Message composer action toolbar |
+| `composer.toolbar.sending` | Sending | Message composer action toolbar |
+| `composer.toolbar.sendMessage` | Send message | Message composer action toolbar |
+| `composer.format.bold` | Bold | Message composer formatting toolbar |
+| `composer.format.italic` | Italic | Message composer formatting toolbar |
+| `composer.format.strikethrough` | Strikethrough | Message composer formatting toolbar |
+| `composer.format.code` | Code | Message composer formatting toolbar |
+| `composer.format.codeBlock` | Code block | Message composer formatting toolbar |
+| `composer.format.link` | Link | Message composer formatting toolbar |
+| `composer.format.bulletList` | Bullet list | Message composer formatting toolbar |
+| `composer.format.orderedList` | Ordered list | Message composer formatting toolbar |
+| `composer.format.quote` | Quote | Message composer formatting toolbar |
+| `composer.format.spoiler` | Spoiler | Message composer formatting toolbar |
+| `composer.format.enterUrl` | Enter URL: | Message composer formatting toolbar |
+| `composer.format.linkText` | Link text: | Message composer formatting toolbar |
+| `composer.banner.editing` | Editing message | Message composer reply or edit banner |
+| `composer.banner.cancelEdit` | Cancel edit | Message composer reply or edit banner |
+| `composer.banner.replying` | Replying to {{author}} | Message composer reply or edit banner |
+| `composer.banner.cancelReply` | Cancel reply | Message composer reply or edit banner |
+| `composer.actions.more` | More actions | Message action bar and overflow menu |
+| `composer.actions.edit` | Edit message | Message action bar and overflow menu |
+| `composer.actions.markRead` | Mark read | Message action bar and overflow menu |
+| `composer.actions.markUnread` | Mark unread | Message action bar and overflow menu |
+| `composer.actions.followThread` | Follow thread | Message action bar and overflow menu |
+| `composer.actions.unfollowThread` | Unfollow thread | Message action bar and overflow menu |
+| `composer.actions.copyMessage` | Copy message | Message action bar and overflow menu |
+| `composer.actions.messageCopied` | Message copied to clipboard | Message action bar and overflow menu |
+| `composer.actions.remindLater` | Remind me later | Message action bar and overflow menu |
+| `composer.actions.copyLink` | Copy link | Message action bar and overflow menu |
+| `composer.actions.linkCopied` | Link copied to clipboard | Message action bar and overflow menu |
+| `composer.actions.report` | Report message | Message action bar and overflow menu |
+| `composer.actions.delete` | Delete message | Message action bar and overflow menu |
+| `composer.actions.openReactions` | Open reactions | Message action bar and overflow menu |
+| `composer.actions.react` | React | Message action bar and overflow menu |
+| `composer.actions.reply` | Reply | Message action bar and overflow menu |
+| `composer.delete.title` | Delete message? | Delete-message confirmation dialog |
+| `composer.delete.description` | This will permanently delete this message and cannot be undone. | Delete-message confirmation dialog |
+| `composer.delete.cancel` | Cancel | Delete-message confirmation dialog |
+| `composer.delete.confirm` | Delete | Delete-message confirmation dialog |
+| `composer.mention.agent` | agent | Message composer mention picker |
+| `composer.mention.teamAgents_one` | team · {{count}} agent | Message composer mention picker |
+| `composer.mention.teamAgents_other` | team · {{count}} agents | Message composer mention picker |
+| `composer.mention.managedBy` | managed by {{owner}} | Message composer mention picker |
+| `composer.mention.notInChannel` | not in channel | Message composer mention picker |
+| `composer.mention.managedByNotInChannel` | managed by {{owner}} · not in channel | Message composer mention picker |
+| `agents.title` | Agents | Agents main screen |
+| `agents.description` | Set up and manage your agents. | Agents main screen |
+| `agents.defaults` | Agent defaults | Agents main screen |
+| `agents.setDefaults` | Set agent defaults | Agents main screen |
+| `agents.stopRunning` | Stop running agents | Agents main screen |
+| `agents.actions` | Agent actions | Agents main screen |
+| `agents.dropToImport` | Drop .agent.json or .agent.png to import | Agents main screen |
+| `agents.unknown` | Unknown agents | Agents main screen |
+| `agents.custom` | Custom agents | Agents main screen |
+| `agents.configurationMissing` | Configuration missing | Agents main screen |
+| `agents.newAgent` | New agent | Agents main screen |
+| `agents.createAgent` | Create agent | Agents main screen |
+| `agents.discoverAgents` | Discover agents | Agents main screen |
+| `agents.import` | Import | Agents main screen |
+| `agents.profile` | {{name}} agent profile | Agents main screen |
+
+Total keys: **140**.
diff --git a/desktop/src/locales/en.json b/desktop/src/locales/en.json
new file mode 100644
index 0000000000..aed3fc0258
--- /dev/null
+++ b/desktop/src/locales/en.json
@@ -0,0 +1,180 @@
+{
+  "settings": {
+    "nav": {
+      "backToApp": "Back to app",
+      "groups": {
+        "personal": "Personal",
+        "communities": "Communities",
+        "app": "App"
+      },
+      "sectionsLabel": "{{group}} settings sections",
+      "sections": {
+        "appearance": "Appearance",
+        "profile": "Profile",
+        "notifications": "Notifications",
+        "experimental": "Experiments",
+        "agents": "Agents",
+        "channelTemplates": "Channel templates",
+        "compute": "Compute",
+        "shortcuts": "Shortcuts",
+        "hostedCommunities": "Hosted communities",
+        "communityMembers": "Invites",
+        "moderation": "Moderation",
+        "customEmoji": "Custom emoji",
+        "localArchive": "Local archive",
+        "mobile": "Mobile",
+        "updates": "Updates"
+      }
+    },
+    "access": {
+      "checking": "Checking invite permissions…",
+      "error": "Invite settings could not be checked.",
+      "retry": "Try again",
+      "unavailable": "Invite settings are unavailable. Relay recovery may still be in progress."
+    },
+    "appearance": {
+      "title": "Appearance",
+      "description": "Choose a theme for Buzz.",
+      "system": "System",
+      "light": "Light",
+      "dark": "Dark",
+      "accentColor": "Accent color",
+      "threadLayout": "Thread layout",
+      "threadFocus": "Focus",
+      "threadFocusDescription": "Threads open over the channel, full width",
+      "threadSplit": "Split",
+      "threadSplitDescription": "Threads open in a side panel next to the channel"
+    },
+    "language": {
+      "label": "Language",
+      "description": "Choose the language used by Buzz.",
+      "english": "English"
+    }
+  },
+  "sidebar": {
+    "primary": {
+      "inbox": "Inbox",
+      "pulse": "Pulse",
+      "projects": "Projects",
+      "agents": "Agents",
+      "workflows": "Workflows"
+    },
+    "community": {
+      "notConnected": "Not connected",
+      "connecting": "Connecting…",
+      "connected": "Connected",
+      "reconnecting": "Reconnecting to relay…",
+      "stalled": "Connection lost — relay is not responding",
+      "disconnected": "Disconnected from relay",
+      "noCommunity": "No community",
+      "community": "Community",
+      "actions": "Community actions",
+      "copyUrl": "Copy community URL",
+      "invite": "Invite to community",
+      "settings": "Community settings",
+      "add": "Add a community",
+      "switch": "Switch community",
+      "edit": "Edit {{name}}"
+    },
+    "channel": {
+      "closeDirectMessage": "Close direct message",
+      "newComments_one": "new comment",
+      "newComments_other": "new comments",
+      "unread": "unread",
+      "copy": "Copy",
+      "copyName": "Copy channel name",
+      "copyId": "Copy channel ID",
+      "nameCopied": "Channel name copied to clipboard",
+      "idCopied": "Channel ID copied to clipboard",
+      "markAsRead": "Mark as read",
+      "markUnread": "Mark unread",
+      "mute": "Mute channel",
+      "unmute": "Unmute channel",
+      "star": "Star channel",
+      "unstar": "Unstar channel",
+      "leave": "Leave channel",
+      "archive": "Archive channel",
+      "delete": "Delete channel"
+    }
+  },
+  "composer": {
+    "toolbar": {
+      "formatting": "Formatting",
+      "toggleFormatting": "Toggle formatting",
+      "closeFormatting": "Close formatting",
+      "mention": "Mention someone",
+      "attachFile": "Attach file",
+      "sending": "Sending",
+      "sendMessage": "Send message"
+    },
+    "format": {
+      "bold": "Bold",
+      "italic": "Italic",
+      "strikethrough": "Strikethrough",
+      "code": "Code",
+      "codeBlock": "Code block",
+      "link": "Link",
+      "bulletList": "Bullet list",
+      "orderedList": "Ordered list",
+      "quote": "Quote",
+      "spoiler": "Spoiler",
+      "enterUrl": "Enter URL:",
+      "linkText": "Link text:"
+    },
+    "banner": {
+      "editing": "Editing message",
+      "cancelEdit": "Cancel edit",
+      "replying": "Replying to {{author}}",
+      "cancelReply": "Cancel reply"
+    },
+    "actions": {
+      "more": "More actions",
+      "edit": "Edit message",
+      "markRead": "Mark read",
+      "markUnread": "Mark unread",
+      "followThread": "Follow thread",
+      "unfollowThread": "Unfollow thread",
+      "copyMessage": "Copy message",
+      "messageCopied": "Message copied to clipboard",
+      "remindLater": "Remind me later",
+      "copyLink": "Copy link",
+      "linkCopied": "Link copied to clipboard",
+      "report": "Report message",
+      "delete": "Delete message",
+      "openReactions": "Open reactions",
+      "react": "React",
+      "reply": "Reply"
+    },
+    "delete": {
+      "title": "Delete message?",
+      "description": "This will permanently delete this message and cannot be undone.",
+      "cancel": "Cancel",
+      "confirm": "Delete"
+    },
+    "mention": {
+      "agent": "agent",
+      "teamAgents_one": "team · {{count}} agent",
+      "teamAgents_other": "team · {{count}} agents",
+      "managedBy": "managed by {{owner}}",
+      "notInChannel": "not in channel",
+      "managedByNotInChannel": "managed by {{owner}} · not in channel"
+    }
+  },
+  "agents": {
+    "title": "Agents",
+    "description": "Set up and manage your agents.",
+    "defaults": "Agent defaults",
+    "setDefaults": "Set agent defaults",
+    "stopRunning": "Stop running agents",
+    "actions": "Agent actions",
+    "dropToImport": "Drop .agent.json or .agent.png to import",
+    "unknown": "Unknown agents",
+    "custom": "Custom agents",
+    "configurationMissing": "Configuration missing",
+    "newAgent": "New agent",
+    "createAgent": "Create agent",
+    "discoverAgents": "Discover agents",
+    "import": "Import",
+    "profile": "{{name}} agent profile"
+  }
+}
diff --git a/desktop/src/locales/zh-Hans.json b/desktop/src/locales/zh-Hans.json
new file mode 100644
index 0000000000..631e3d1159
--- /dev/null
+++ b/desktop/src/locales/zh-Hans.json
@@ -0,0 +1,180 @@
+{
+  "settings": {
+    "nav": {
+      "backToApp": "返回应用",
+      "groups": {
+        "personal": "个人",
+        "communities": "社区",
+        "app": "应用"
+      },
+      "sectionsLabel": "{{group}}设置项",
+      "sections": {
+        "appearance": "外观",
+        "profile": "个人资料",
+        "notifications": "通知",
+        "experimental": "实验",
+        "agents": "Agents",
+        "channelTemplates": "频道模板",
+        "compute": "Compute",
+        "shortcuts": "快捷键",
+        "hostedCommunities": "托管的社区",
+        "communityMembers": "邀请",
+        "moderation": "管理",
+        "customEmoji": "自定义 Emoji",
+        "localArchive": "本地存档",
+        "mobile": "移动端",
+        "updates": "更新"
+      }
+    },
+    "access": {
+      "checking": "正在检查邀请权限…",
+      "error": "无法检查邀请设置。",
+      "retry": "重试",
+      "unavailable": "邀请设置不可用。中继恢复可能仍在进行中。"
+    },
+    "appearance": {
+      "title": "外观",
+      "description": "选择 Buzz 的主题。",
+      "system": "跟随系统",
+      "light": "浅色",
+      "dark": "深色",
+      "accentColor": "强调色",
+      "threadLayout": "Thread 布局",
+      "threadFocus": "焦点",
+      "threadFocusDescription": "Thread 在频道上方打开，全宽显示",
+      "threadSplit": "分屏",
+      "threadSplitDescription": "Thread 在频道旁边的侧面板打开"
+    },
+    "language": {
+      "label": "语言",
+      "description": "选择 Buzz 使用的语言。",
+      "english": "英文"
+    }
+  },
+  "sidebar": {
+    "primary": {
+      "inbox": "收件箱",
+      "pulse": "动态",
+      "projects": "项目",
+      "agents": "Agents",
+      "workflows": "Workflows"
+    },
+    "community": {
+      "notConnected": "未连接",
+      "connecting": "连接中…",
+      "connected": "已连接",
+      "reconnecting": "正在重新连接中继…",
+      "stalled": "连接丢失 - 中继无响应",
+      "disconnected": "已断开中继连接",
+      "noCommunity": "无社区",
+      "community": "社区",
+      "actions": "社区操作",
+      "copyUrl": "复制社区链接",
+      "invite": "邀请加入社区",
+      "settings": "社区设置",
+      "add": "添加社区",
+      "switch": "切换社区",
+      "edit": "编辑{{name}}"
+    },
+    "channel": {
+      "closeDirectMessage": "关闭私信",
+      "newComments_one": "条新评论",
+      "newComments_other": "条新评论",
+      "unread": "未读",
+      "copy": "复制",
+      "copyName": "复制频道名称",
+      "copyId": "复制频道 ID",
+      "nameCopied": "频道名称已复制到剪贴板",
+      "idCopied": "频道 ID 已复制到剪贴板",
+      "markAsRead": "标为已读",
+      "markUnread": "标为未读",
+      "mute": "静音频道",
+      "unmute": "取消静音",
+      "star": "星标频道",
+      "unstar": "取消星标频道",
+      "leave": "离开频道",
+      "archive": "归档频道",
+      "delete": "删除频道"
+    }
+  },
+  "composer": {
+    "toolbar": {
+      "formatting": "格式",
+      "toggleFormatting": "切换格式",
+      "closeFormatting": "关闭格式",
+      "mention": "提及某人",
+      "attachFile": "添加文件",
+      "sending": "发送中",
+      "sendMessage": "发送消息"
+    },
+    "format": {
+      "bold": "加粗",
+      "italic": "斜体",
+      "strikethrough": "删除线",
+      "code": "代码",
+      "codeBlock": "代码块",
+      "link": "链接",
+      "bulletList": "无序列表",
+      "orderedList": "有序列表",
+      "quote": "引用",
+      "spoiler": "隐藏内容",
+      "enterUrl": "输入 URL：",
+      "linkText": "链接文字："
+    },
+    "banner": {
+      "editing": "正在编辑消息",
+      "cancelEdit": "取消编辑",
+      "replying": "正在回复 {{author}}",
+      "cancelReply": "取消回复"
+    },
+    "actions": {
+      "more": "更多",
+      "edit": "编辑消息",
+      "markRead": "标记已读",
+      "markUnread": "标记未读",
+      "followThread": "关注讨论",
+      "unfollowThread": "取消关注讨论",
+      "copyMessage": "复制消息",
+      "messageCopied": "消息已复制到剪贴板",
+      "remindLater": "稍后提醒",
+      "copyLink": "复制链接",
+      "linkCopied": "链接已复制到剪贴板",
+      "report": "举报消息",
+      "delete": "删除消息",
+      "openReactions": "打开回应",
+      "react": "回应",
+      "reply": "回复"
+    },
+    "delete": {
+      "title": "删除消息？",
+      "description": "将永久删除此消息，且无法撤销。",
+      "cancel": "取消",
+      "confirm": "删除"
+    },
+    "mention": {
+      "agent": "agent",
+      "teamAgents_one": "团队 · {{count}} 个 agent",
+      "teamAgents_other": "团队 · {{count}} 个 agent",
+      "managedBy": "由 {{owner}} 管理",
+      "notInChannel": "不在频道中",
+      "managedByNotInChannel": "由 {{owner}} 管理 · 不在频道中"
+    }
+  },
+  "agents": {
+    "title": "Agents",
+    "description": "设置和管理您的 agents。",
+    "defaults": "Agent 默认设置",
+    "setDefaults": "设置 agent 默认值",
+    "stopRunning": "停止运行中的 agent",
+    "actions": "Agent 操作",
+    "dropToImport": "拖放 .agent.json 或 .agent.png 文件以导入",
+    "unknown": "未知 agents",
+    "custom": "自定义 agents",
+    "configurationMissing": "缺少配置",
+    "newAgent": "新建 agent",
+    "createAgent": "创建 agent",
+    "discoverAgents": "发现 agents",
+    "import": "导入",
+    "profile": "{{name}} agent 资料"
+  }
+}
diff --git a/desktop/src/locales/zh-Hant.json b/desktop/src/locales/zh-Hant.json
new file mode 100644
index 0000000000..19d7efaa77
--- /dev/null
+++ b/desktop/src/locales/zh-Hant.json
@@ -0,0 +1,180 @@
+{
+  "settings": {
+    "nav": {
+      "backToApp": "返回",
+      "groups": {
+        "personal": "個人",
+        "communities": "社群",
+        "app": "App"
+      },
+      "sectionsLabel": "{{group}} 設定",
+      "sections": {
+        "appearance": "外觀",
+        "profile": "個人檔案",
+        "notifications": "通知",
+        "experimental": "實驗功能",
+        "agents": "Agents",
+        "channelTemplates": "頻道範本",
+        "compute": "Compute",
+        "shortcuts": "捷徑",
+        "hostedCommunities": "託管社群",
+        "communityMembers": "邀請",
+        "moderation": "管理",
+        "customEmoji": "自訂 emoji",
+        "localArchive": "本機存檔",
+        "mobile": "手機",
+        "updates": "更新"
+      }
+    },
+    "access": {
+      "checking": "正在檢查邀請權限…",
+      "error": "無法檢查邀請設定。",
+      "retry": "重試",
+      "unavailable": "邀請設定暫時無法使用。中繼復原可能仍在進行中。"
+    },
+    "appearance": {
+      "title": "外觀",
+      "description": "為 Buzz 選擇主題。",
+      "system": "系統",
+      "light": "淺色",
+      "dark": "深色",
+      "accentColor": "重點顏色",
+      "threadLayout": "討論串佈局",
+      "threadFocus": "聚焦",
+      "threadFocusDescription": "討論串以全寬度覆蓋頻道打開",
+      "threadSplit": "分割",
+      "threadSplitDescription": "討論串在頻道旁邊嘅側邊面板打開"
+    },
+    "language": {
+      "label": "語言",
+      "description": "選擇 Buzz 使用嘅語言。",
+      "english": "英文"
+    }
+  },
+  "sidebar": {
+    "primary": {
+      "inbox": "收件匣",
+      "pulse": "Pulse",
+      "projects": "Projects",
+      "agents": "Agents",
+      "workflows": "Workflows"
+    },
+    "community": {
+      "notConnected": "未連接",
+      "connecting": "連接中…",
+      "connected": "已連接",
+      "reconnecting": "正在重新連接 relay…",
+      "stalled": "連線中斷 — relay 無回應",
+      "disconnected": "已中斷連接 relay",
+      "noCommunity": "沒有社群",
+      "community": "社群",
+      "actions": "社群操作",
+      "copyUrl": "複製社群網址",
+      "invite": "邀請加入社群",
+      "settings": "社群設定",
+      "add": "新增社群",
+      "switch": "切換社群",
+      "edit": "編輯 {{name}}"
+    },
+    "channel": {
+      "closeDirectMessage": "關閉 DM",
+      "newComments_one": "新留言",
+      "newComments_other": "新留言",
+      "unread": "未讀",
+      "copy": "複製",
+      "copyName": "複製 Channel 名稱",
+      "copyId": "複製 Channel ID",
+      "nameCopied": "已複製 Channel 名稱",
+      "idCopied": "已複製 Channel ID",
+      "markAsRead": "標為已讀",
+      "markUnread": "標為未讀",
+      "mute": "靜音 Channel",
+      "unmute": "取消靜音 Channel",
+      "star": "星標 Channel",
+      "unstar": "取消星標 Channel",
+      "leave": "離開頻道",
+      "archive": "封存頻道",
+      "delete": "刪除頻道"
+    }
+  },
+  "composer": {
+    "toolbar": {
+      "formatting": "格式",
+      "toggleFormatting": "切換格式",
+      "closeFormatting": "關閉格式",
+      "mention": "提及",
+      "attachFile": "附加檔案",
+      "sending": "傳送中",
+      "sendMessage": "傳送訊息"
+    },
+    "format": {
+      "bold": "粗體",
+      "italic": "斜體",
+      "strikethrough": "刪除線",
+      "code": "程式碼",
+      "codeBlock": "程式碼區塊",
+      "link": "連結",
+      "bulletList": "項目清單",
+      "orderedList": "編號清單",
+      "quote": "引用",
+      "spoiler": "劇透",
+      "enterUrl": "輸入網址：",
+      "linkText": "連結文字："
+    },
+    "banner": {
+      "editing": "改緊訊息",
+      "cancelEdit": "取消編輯",
+      "replying": "回覆緊 {{author}}",
+      "cancelReply": "取消回覆"
+    },
+    "actions": {
+      "more": "更多選項",
+      "edit": "編輯訊息",
+      "markRead": "標示為已讀",
+      "markUnread": "標示為未讀",
+      "followThread": "追蹤討論串",
+      "unfollowThread": "取消追蹤討論串",
+      "copyMessage": "複製訊息",
+      "messageCopied": "訊息已複製到 clipboard",
+      "remindLater": "遲啲提醒我",
+      "copyLink": "複製連結",
+      "linkCopied": "已複製連結",
+      "report": "舉報訊息",
+      "delete": "刪除訊息",
+      "openReactions": "查看 reactions",
+      "react": "加 reaction",
+      "reply": "回覆"
+    },
+    "delete": {
+      "title": "刪除訊息？",
+      "description": "會永久刪除呢個訊息，冇得復原。",
+      "cancel": "取消",
+      "confirm": "刪除"
+    },
+    "mention": {
+      "agent": "agent",
+      "teamAgents_one": "team · {{count}} 個 agent",
+      "teamAgents_other": "team · {{count}} 個 agents",
+      "managedBy": "由 {{owner}} 管理",
+      "notInChannel": "唔喺 channel",
+      "managedByNotInChannel": "由 {{owner}} 管理 · 唔喺 channel"
+    }
+  },
+  "agents": {
+    "title": "Agents",
+    "description": "設定同管理你啲 agents。",
+    "defaults": "Agent 預設",
+    "setDefaults": "設定 agent 預設值",
+    "stopRunning": "停止 agents",
+    "actions": "Agent 操作",
+    "dropToImport": "拖放 .agent.json 或 .agent.png 匯入",
+    "unknown": "不明 agents",
+    "custom": "自訂 agents",
+    "configurationMissing": "未有 configuration",
+    "newAgent": "新增 agent",
+    "createAgent": "建立 agent",
+    "discoverAgents": "探索 agents",
+    "import": "匯入",
+    "profile": "{{name}} 嘅 agent profile"
+  }
+}
diff --git a/desktop/src/main.tsx b/desktop/src/main.tsx
index d2751dfe16..44392f673b 100644
--- a/desktop/src/main.tsx
+++ b/desktop/src/main.tsx
@@ -1,5 +1,6 @@
 import React from "react";
 import ReactDOM from "react-dom/client";
+import "@/i18n";
 import { App } from "@/app/App";
 import { NostrBindConsentDialog } from "@/features/profile/ui/NostrBindConsentDialog";
 import "@fontsource-variable/inter/wght.css";
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 746aab05e6..8e8bbc22ac 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -186,6 +186,9 @@ importers:
       emoji-mart:
         specifier: ^5.6.0
         version: 5.6.0
+      i18next:
+        specifier: ^25.10.5
+        version: 25.10.5(typescript@6.0.3)
       jdenticon:
         specifier: ^3.3.0
         version: 3.3.0
@@ -210,6 +213,9 @@ importers:
       react-dom:
         specifier: ^19.1.0
         version: 19.2.8(react@19.2.8)
+      react-i18next:
+        specifier: ^16.6.2
+        version: 16.6.2(i18next@25.10.5(typescript@6.0.3))(react@19.2.8)(typescript@6.0.3)
       react-markdown:
         specifier: ^10.1.0
         version: 10.1.0(@types/react@19.2.17)(react@19.2.8)
@@ -2581,6 +2587,9 @@ packages:
     resolution: {integrity: sha512-CV9TW3Y3f8/wT0BRFc1/KAVQ3TUHiXmaAb6VW9vtiMFf7SLoMd1PdAc4W3KFOFETBJUb90KatHqlsZMWV+R9Gg==}
     engines: {node: ^20.19.0 || ^22.12.0 || >=24.0.0}
 
+  html-parse-stringify@3.0.1:
+    resolution: {integrity: sha512-KknJ50kTInJ7qIScF3jeaFRpMpE8/lfiTdzf/twXyPBLAGrLRTmkz3AdTnKeh40X8k9L2fdYwEp/42WGXIRGcg==}
+
   html-url-attributes@3.0.1:
     resolution: {integrity: sha512-ol6UPyBWqsrO6EJySPz2O7ZSr856WDrEzM5zMqp+FJJLGMW35cLYmmZnl0vztAZxRUoNZJFTCohfjuIJ8I4QBQ==}
 
@@ -2595,6 +2604,14 @@ packages:
     resolution: {integrity: sha512-vK9P5/iUfdl95AI+JVyUuIcVtd4ofvtrOr3HNtM2yxC9bnMbEdp3x01OhQNnjb8IJYi38VlTE3mBXwcfvywuSw==}
     engines: {node: '>= 14'}
 
+  i18next@25.10.5:
+    resolution: {integrity: sha512-jRnF7eRNsdcnh7AASSgaU3lj/8lJZuHkfsouetnLEDH0xxE1vVi7qhiJ9RhdSPUyzg4ltb7P7aXsFlTk9sxL2w==}
+    peerDependencies:
+      typescript: ^5
+    peerDependenciesMeta:
+      typescript:
+        optional: true
+
   ieee754@1.2.1:
     resolution: {integrity: sha512-dcyqhDvX1C46lXZcVqCpK+FtMRQVdIMN6/Df5js2zouUsqG7I6sFxitIC+7KYK29KdXOLHdu9zL4sFnoVQnqaA==}
 
@@ -3185,6 +3202,20 @@ packages:
     peerDependencies:
       react: ^19.2.8
 
+  react-i18next@16.6.2:
+    resolution: {integrity: sha512-/S/GPzElTqEi5o2kzd0/O2627hPDmE6OGhJCCwCfUaQ3syyu+kaYH8/PYFtZeWc25NzfxTN/2fD1QjvrTgrFfA==}
+    peerDependencies:
+      i18next: '>= 25.6.2'
+      react: '>= 16.8.0'
+      typescript: ^5
+    peerDependenciesMeta:
+      react-dom:
+        optional: true
+      react-native:
+        optional: true
+      typescript:
+        optional: true
+
   react-is@17.0.2:
     resolution: {integrity: sha512-w2GsyukL62IJnlaff/nRegPQR94C/XXamvMWmSHRJ4y7Ts/4ocGRmTHvOs8PSE6pB3dWOrD/nueuU5sduBsQ4w==}
 
@@ -3630,6 +3661,10 @@ packages:
       jsdom:
         optional: true
 
+  void-elements@3.1.0:
+    resolution: {integrity: sha512-Dhxzh5HZuiHQhbvTW9AMetFfBHDMYpo23Uo9btPXgdYP+3T5S+p+jgNy7spra+veYhBP2dCSgxR/i2Y02h5/6w==}
+    engines: {node: '>=0.10.0'}
+
   w3c-keyname@2.2.8:
     resolution: {integrity: sha512-dpojBhNsCNN7T82Tm7k26A6G9ML3NkhDsnw9n/eoxSRlVBB4CEtIQ/KTCLI2Fwf3ataSXRhYFkQi3SlnFwPvPQ==}
 
@@ -5788,6 +5823,10 @@ snapshots:
     transitivePeerDependencies:
       - '@noble/hashes'
 
+  html-parse-stringify@3.0.1:
+    dependencies:
+      void-elements: 3.1.0
+
   html-url-attributes@3.0.1: {}
 
   html-void-elements@3.0.0: {}
@@ -5806,6 +5845,12 @@ snapshots:
     transitivePeerDependencies:
       - supports-color
 
+  i18next@25.10.5(typescript@6.0.3):
+    dependencies:
+      '@babel/runtime': 7.29.7
+    optionalDependencies:
+      typescript: 6.0.3
+
   ieee754@1.2.1: {}
 
   ignore@5.3.2: {}
@@ -6593,6 +6638,16 @@ snapshots:
       react: 19.2.8
       scheduler: 0.27.0
 
+  react-i18next@16.6.2(i18next@25.10.5(typescript@6.0.3))(react@19.2.8)(typescript@6.0.3):
+    dependencies:
+      '@babel/runtime': 7.29.7
+      html-parse-stringify: 3.0.1
+      i18next: 25.10.5(typescript@6.0.3)
+      react: 19.2.8
+      use-sync-external-store: 1.6.0(react@19.2.8)
+    optionalDependencies:
+      typescript: 6.0.3
+
   react-is@17.0.2: {}
 
   react-markdown@10.1.0(@types/react@19.2.17)(react@19.2.8):
@@ -7034,6 +7089,8 @@ snapshots:
     transitivePeerDependencies:
       - msw
 
+  void-elements@3.1.0: {}
+
   w3c-keyname@2.2.8: {}
 
   w3c-xmlserializer@5.0.0: