Keys from my keyboard (A brazilian one, that includes symbols such as: "Ç", and has keys that are placed differently, like: ~ ] [ ´ . , ') may sometimes swap from an American keyboard. (I may be wrong, since I've never actually seen an American one.)
After they swap, for example, Ç becomes ', ´ becomes [ and [ becomes ]. Stuff like this. This may not be such a serious problem because the ABC alphabet is still flawless.