[Hellblazer]

Written words into a log sounds a very good idea. But at the same time I'd limit the amount of word you could write in a x number of time (I'd say x numbers of days really), to give a perspective of time. This way it would promote a continual rp into learning the language, and limit the abuse of someone actually writing the whole dictionary at once.

I'm not sure if there is a natural stat system (int, con etc) but if there is something like that or similar, then the number of language learn should be defined by how intelligent your char is.