It's a well-known rule at the WSOP that only English can be spoken at the table to prevent collusion between two players speaking a language the rest of the players at the table don't understand.
Russians, in particular, have been allegedly guilty of this several times.
In a recent hand in the $3,000 Triple Chance tournament, Andrew Scott found himself in between two Russians and after a seeing the flop he heard one of them say something to the other in Russian.
Scott asked the Russian on his left what he had said but the player didn't answer. Scott was perturbed by the hand and decided to call over the floor manager at this point.
After listening to the issue the floor manager simply reiterated to the Russian players that they had to speak English at the table.
Scott seemed pleased with the resolution and even joked with one of the Russian players after the incident.
"If you're going to do that you shouldn't wear a Russian flag on your sweater," joked Scott. "It makes it easier to tell you're speaking Russian!"