LOL I catch my self doing this a lot. It's embarrassing when it happens in a public place. Sometimes I talk to myself on purpose, to get my head together, or sometimes end up talking to myself when I'm really stressed out. Sometimes when I'm in bad shape I end up replaying things in my head that have happened in the past and talking out loud like I'm still in the situation, and then come back to reality and I'm at work with other people around, and then I feel stupid

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It's the worst, though, when you're in a public bathroom or on the bus. Sometimes I think about words or phrases in other languages when I'm off in my own little world and try to pronounce them out loud without thinking first that I'm in front of other people.
Usually, though, I laugh out loud about things that are funny in my head and then can't explain to people why I'm laughing because they wouldn't get it.
I don't really know what all of this means, but I'm pretty sure it's normal and that most people accidentally talk out loud to themselves.