Came to make the same comment. Normally, I avoid giving the "Me Too!" comments, but I think in this context it's appropriate. If I'm casually thinking about life, the universe, and everything then I typically have a monologue. I don't "hear" it, per say, but I am thinking in sentence structure. If I'm analyzing a problem, working on a project, or trying to digest a situation, then I do not think in such sentence like ways. If I'm performing a low-cognitive-load activity (like a long road-trip), then I've got an inner-monologue going on with words & sentences. If I'm really in need of my focus (driving in Manhattan), there's zero inner-monologue.