Eh, how about every session you have players draw straws. The one who wins gets the Language Card for the session, and they have to come up with a reason why they speak the particular language of the week. These reasons should a) not be repeated and b) get more outlandish as the campaign progresses. From "I studied it at MIT" to "As a child, my father took in an orphan goatherd from a small tribe just outside of 'blah', which is remarkably similar to 'foo'!"