Currently addon replaces letters on letter-per-letter base.

It isn't a problem if your character can pronounce that letter to another faction. Problems start with unpronounceable letters. Addon solves it through substitution of some letters for others. For example, Common language lacks letter C. Currently, it just replaces C with K. So, if you try typing different words as human to orc, they will see:

So, it would be nice if addon were aware of pronunciation specifics.