You don't say

Sorry
could you be more specific about it?
Thank you

I think Dr. Briggs is as specific as you can get. Conversation in English is often full of expressions not to be taken literally, sometimes best translated as "I'm listening, keep going." In my youth "You don't say!" meant "Really? I find that interesting, keep talking." The speaker, for his or her part, would often say, "Don'tcha know?," while one might hear nowadays, "Ya know?" I suppose these and many other expressions could be termed as grease to help the conversation keep moving. SS