I've noticed that I can do both the monologue thing and also the nonverbal thinking, and I suspect that most people can do both also.

I do verbal thinking when I'm by myself and thinking through options. What should I have for dinner? What gift should I buy? That kind of thing.

Non-verbal thought is when I'm totally focused on something like a competitive game. When I'm 100% in the zen-like focus of moment to moment instinctive action, there's "no time" for monologuing.