The question was, "Can you understand me?" I had 2 answers in my head, polite and informal -
Pouvez-vous me comprenez ?
Peux-tu me comprendre ?
The correct was Est-ce que vous me comprenez ?
I understand that "est-ce que" is used to turn a statement into question and can't be translated literally to English. Secondly what happened to the word "can" in the question and lastly when do we use "pouvez-vous and peux-tu" if "est-ce que vous me comprenez" is correct or better answer?