Another string distance possibility

[richfitz]

https://github.com/wsong/Typo-Distance

Thus, for instance, "rlephants" is a fairly likely typo of "elephants" on a QWERTY keyboard, since R is fairly close to E, but "ilephants" is a less likely typo, and therefore would have a higher score. One thing to note is that typoDistance is not commutative, since insertions are considered more costly than deletions.

would need modifications for AZERTY/QWERTZ keyboards etc, but could be interesting to try.