A very annoying and disrespecful phenomena in the EU servers only the players can solve.
Please stop speaking languages other than English while in game. Just stop! You have a duo? cool! there are 3 more people in your team who deserve to know what are you planning on doing in their game! And if you have at least minimal respect even if there's even 1 guy who doesn't speak your language then DONT SPEAK IT! It got to a point where I get flamed and threatened to be reported for racism by an entire team because I asked them to speak English? Are you serious EUNE?! My native language is far from being English but never did I speak with someone in my own language in the game itself and trust me there are plenty. It's even for your own good! How can you expect cooperation from teamates who have no clue what are you going to do?! I don't think a Rioter would see this (or even care enough if he would),but please make an option after game that says "refusing to communicate" or something like that. Don't make it a punishable offense but make it so if people do complain about this for a specific player then he will get a notification encouraging him to stop it.