do you talk to yourself in real time?

Slightly faster. (Also, my inner monologue is usually in standard, formal language, whereas when I actually talk to people I tend to use many more regional colloquialisms.)

How does reading feel in comparison?

Usually faster, because I'm processing existing content rather than generating it from scratch. But when I'm reading stuff by people whose voice I'm familiar with, or poetry, I tend to subvocalize much more vividly, and pretty much in real time.

When you recall a conversation, do you re-verbalize the content?

Sometimes I do; other times, I can't even remember what language it was in.

Can you speak without knowing what you're about to say beforehand?

I usually do in small talk, but not in technical conversations. (And in the former, I sometimes stop myself mid-sentence because I don't like what I've said or I come up with something better to say, and immediately start an entirely new sentence.)