I was watching the streaming for a while. He was responding to those who greeted him in Turkish, and was constantly chatting with his Turkish-German friends. And his friends spoke Turkish most of the time.
In my book he speaks German with his friends and yea, he can say Salem aleykum but not much more. Doesnβt matter though, he and gob are insane players and all fans of BIG love Turks anyways :)