I get a combination of both.

The thoughts I have day to day, as I work or whatever, are mostly silent thoughts that instantly become actions, reactions, words out of my mouth, things I type, so on and so forth...

... But when I think about something, like sit back and take it in, it becomes almost conversational. I think the whole sentence through in my head as if I were speaking it aloud and, as I understand it, some research suggests that we actually move our vocal cords at an almost imperceptible level while doing this. I ask questions, answer questions, form full thoughts and ideas, toss them back and forth, debate them, question them to pick apart obvious flaws and preempt any issue that I might have or run into or others might rise... In short, I really get into it with myself. That guy's an arsehole, by the by. If you had half the conversations I have with me, you'd think I was a real tool!

So, yeah, it's a bit of both. Most of the things that don't require real focus are almost instinctual. Things, like this post, that require me to express or really consider something are more like internal plays where I act out the outcomes aloud in my head, question the meanings as if there were a second actor or point out the flaws as if there were mean spirited accusers trying to drag the idea through the dirt.

Could be I'm insane, but I've worked it into a viable system for now. Anyway, gotta go count my jars full of captured human voices. Thanks for listening!