"Whom are you talking to?" Is it a correct question?
I mean an ordinary situation, when I see someone talking the phone and I want to know who is on the other side of the phone line.

Question

"Whom are you talking to?"  Is it a correct question?
I mean an ordinary situation, when I see someone talking the phone and I want to know who is on the other side of the phone line.

Answer

Hi Mikhail, "who are you talking to?" or "to whom are you talking?".

Hope this helps.
Sinead

Answer

Grammatically? 
I suppose "Whom are you talking to?" and "To whom are you speaking?" are correct. However, they are unnatural. We rarely use "whom" and when we do it's in a more formal situation.
We usually just say "Who are you talking to?" Or "Who is it?"