"Who is talking with them?"

Translation: Wer spricht mit ihnen?

[Terieri]

Why not "Wem sprechen Sie?"

[Steve254604]

Or could this also be "Wer spricht damit?", instead of "Wer spricht mit ihnen?" Would one of these be more common (or encouraged) in this instance?

[mizinamo]

Wer spricht damit? means "Who speaks with it?" and not "...with them?".

[Steve254604]

Thanks. Time for a long sigh, followed by a review of the “da” words as to what “da” can replace... I had had it in my head that “da” was a catch-all for any third-person pronoun.

[mizinamo]

da(r)- is mostly for das, sometimes for es. I don't think it can be used with any other third-person pronoun.