To give some insight into what "monologue people" perceive: I don't exactly hear an actual voice, that would drive me crazy. I cannot do good multitasking with anything verbal going on. If someone is talking to me, I cannot do anything else that also requires my inner monologue well. I can drive a car, which doesn't require my inner monologue, and have a conversation with the passenger, but I cannot program or plan something while someone is talking into my ear all the time.

But the monologue is there, almost uninterrupted. It's just that very often I don't notice it. I have a hard time ignoring actual voices, unless there is some sea of other background noises or chatter.