This also happened to me yesterday in a freeroll at Carbon Poker
. Two people were speaking a foreign language; their avatars were the Swedish flag, so I'm not sure if Swedish is a language or not. The one was a complete donk and kept going in every hand. I couldn't tell if they were colluding or not, but it didn't appear to be the case. Eventually, the problem sort of worked itself out; I got moved to another table, fixing the problem.
I would recommend, in the future, just asking them politely to just speak English at the table. Most of the time, people will probably accept it and either stop talking or keep talking in English. If not, there are pretty much only two things you can do about it. Like mentioned above, you could report the incident to higher authorities as it is against the rules. Or, you could just try to ignore it. I know it gives them an unfair advantage, but it shouldn't really affect your
game all that much. Regardless of how much they know, the only tool available to you is to play your game with your skills. It will be that much sweeter when you knock them out.
Hang in there!