Yes, sometimes I do. It helps me to lay problems out before myself. I usually don't do it unless I'm working on something, though, and even then, it's just mumbling. That usually gets combined with a stim...usually rocking or tearing the mucosa off the inside of my mouth repeatedly.
Funny story, once, before I worked there, I went to an Apple Store and ended up working with the Genius to fix my problem instead of him doing it for me. My mom asked "Do you all do that?" in regards to the tearing of the inside of our mouths. I thought she was referring to Mac users, but she may have just been talking about nerds in general. The Genius and I just looked at each other for a second, then went back to work.