Pretty much comes down to Players needing to seek teachers for the various languages, Balok, Elven, Hin, Dwarven, or gnomish.
Id rather not see a player that rps his character as only holding conversation with his hin friends, or his elven friends, blah blah blah, you get the picture, and then say they know and speak Balok or some other language. I think its very cheesy and it breaks immersion of the setting, racial basis, and nationality.
I will point out again, that it is highly unlikely that Barovians wont teach their language or anything else to a nonbarovian, unless they absolutely like the person, which is again unlikely, youd need to find a teacher that is willing, with a few years of practice, or youre just a stupidly insane smart person, but then itd pretty much take almost the same amount of time and a Teacher.
This also goes in hand with the other languages i mentioned, not just Balok.