Welcome to the forums! hope you find lots of good information. You said you were newly diagnosed I think so I'll give you my standard new/trying to com to terms with it all, www.psychinformation.org It's written by a psychiatrist who specializes in BP and has tons of information. On to your actual question:

I don't think it is necessarily because I have bipolar but I do find myself talking to myself a lot at home (I live alone), nearly as much in the car and sometimes back when I could go in stores I'd whisper to myself if I was getting frustrated with where things were, the cost, etc I don't think anyone ever noticed as I never got a weird look. That's he thing about humans, we're so stuck on ourselves it takes a lot for someone else to notice.