Q:

How do you ask in French: "Are you STILL sleeping?"

I know that "Est-ce que tu dors?" is "Are you sleeping?" but how would you ask "Are you STILL sleeping?"

A:

« Dors-tu encore ? » or you could say too « Es-tu toujours endormi ? » 
Encore and toujours meaning still.
Hmmmm... "Es-tu toujours endormi?" might be seen also as deprecatory. Meaning: "Are you always so asleep as not seeing anything?!?!? (or whatever was expected)?" In fact, in that case "Dors-tu encore?" is a more accurately translated by: Are you still asleep?

A:

Out of any context, a plain "est-ce que tu dors encore?" comes to mind.

