I talk with person , but suddenly I am starting not to understand him. How do I say correctly:
1) "What have you said" or What did you say"?
2) "Did you understand me" or "Have you understood me?"

Question

I talk with person , but suddenly I am starting not to understand him. How do I say correctly:
1) "What have you said" or What did you say"?
2) "Did you understand me" or  "Have you understood me?"

Answer

1) "what did you say?" seems offensive to me. like I said something bad. I think it's better to say. I didn't understand what you just said.
2) "Did you understand me?" or "Did you understand what I mean?"

Answer

1)If you don't then make it clear to him so that he can try to explain it better. Say something like, "I didn't understand you. What did you say?"  If you want to be more polite, try saying "I didn't understand that, could you repeat it please?"

2)  Did you understand me? Or Do you understand what I'm saying?

Answer

Excuse me, I didn't get what you have just said. Could you say it again in a simpler way, please.