you mean talking out loud, right? there's a guy down the street that does that. he's older, maybe in his 50's or 60's and he lives alone. one day i was walking by and he was working in his yard. he was having some sort of arguement (out loud) with no one, but then he got angry and started swearing. well, i just walked as fast as i could to get away.
it's probably normal if you keep it in control.