Thank you! I think I was lucky, being bulgarian and knowing how most of slavanian languages sound like. Also I can very easily distinguish between non-slavanian west-european ones (french, german, italian, spanish, portuguese).
My only advice is to avoid having the same language, or at least same wave file being played twice in a row (It happened few times with me, and I've played it for 5 times in a row).
Also maybe introduce something like in the TV shows, where you can get use "jokers" (hints) such as - remove half of the languages that are not (when there are more than 4 or 5 I guess), etc.
Or maybe let the player risk, by asking for more languages even on lower levels, but for more points.
It's entertaining :) I was actually thinking if you are in the car, and listening to this as a game how would one be able to answer (google glass with eye tracking?), or maybe that's just bad idea for driving.