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It depends exactly what you mean. "speak on" and "talk on" I think are much more likely if it's sort of a performance, not just a conversation. People are watching. "The professor will be speaking on mathematics in the lecture hall this evening" - he'll stand up in front of people and give a speech, on his own. "On our podcast yesterday we talked on our favourite murders" - we had a discussion about them so that people could listen to what we said.

If you just want to have a normal conversation, "can you talk about this topic?".

"talk to you" is by far the most common way to say this. "speak to you" and "speak with you" are both very common and mean exactly the same thing. "talk with you" is, I think, not very common - I feel like I'd rather say "can I have a talk with you", not "can I talk with you" - but I believe it's correct.