I suspect that most people have a partial internal monologue, whereby some thoughts arise to the level of verbiage and others don’t. There is also variance in how self-aware we are of our thoughts themselves. I don’t think anyone can keep up effective, meta self-monitoring 100% of the time, so our own view of our thought process is probably skewed as well. Some people swear that every single thought they have is 100% verbalized. I think that’s impossible and they’re only counting verbal thoughts as thoughts. But no doubt some people verbalize more than others.