On my previous laptop, there was an ability to change between multiple keyboard languages (i forget the keystrokes). But it was bloody annoying because it randomly changed on me for no reason. The / key ended up being some square icon of a symbol the game coundn't recognize and filled it in with that. And as we all know the / key (especially in ff11 and 14 and most other games) is used to initiate a chat window. I ended up deleting the french and other keyboard types to fix the problem. But yours sounds odd if its only the F key. It's possible the F key has an alternate symbol thats getting triggered in the game instance somehow.