Permanently Banned for speaking my language in League Of Legends with friends.

I was in ranked game and then notification popped out that I am banned for 2 weeks, I went to check e-mail to see what happend, no logs found. I relogged to my account and it shown permenently banned. Guess why? Because I was speaking my language (Serbian) with my friends in-game. Does that mean every Polish player that told me kurwa, and all things about my mother should be banned as well? Or players that speak their own language inside a game. Riot explain.