Of course I do. How else would I be able to remain calm in this crazy world? Besides, the conversations I have with myself are usually the best.... or the worst..... Really depends on how I feel. Isn't that right me? ...... Me agrees.
I do it as a way of working out problems, as well as figuring out how I want a conversation to play out. If I have something very important to say, I'll say it out loud first to make sure I know how I want to say it. I also use it to psych myself up for accomplishing things.