I think almost entirely in images, usually moving and relating to each other in 3D space.

There are words mixed in, but when they come up they are usually just single words or a phrases which are attributes of something I'm thinking of, or an action I should take.

Sometimes I think more in words, but that's usually when something is really unclear to me or if I am obsessing over something.

I think that years of training myself not to obsess over things probably reduced my internal monologue almost to the point that it would be good to have a bit more of it sometimes.