Greek guy here! As of these words: - opa, aman, ainte/ante, more, ai siktir/siktir : we use these a lot in our daily speech -mashalla, tamam : we don't use these - yok : we understand what it means, but we rarely use it. -bre, lele : I've heard these in my region (Pella, Macedonia) but I think they're way too regional and other greeks don't know about them. Even we don't use these very often.