Player Language Skill Gains

[pfyon]

I'm in the process of modifying all the quests/chat interaction with npcs so the npcs speak their native language, and won't respond unless the player uses that language as well. This is an attempt to make languages seem more meaningful.

Where is the code stored for language skill gains? I'm wondering if it's possible to give players the abillity to skillup in languages by listening to npcs speak. On live, you could gain skill points by practicing speaking/listening to other people speak the language.