I personally speak alone a lot, I know it's a little bit weird but yeah I often do it. But I do stutter sometimes even alone, especially when I imagine myself re-living a situation and I wish I said this instead of that. But when I just randomly speak alone I do not stutter most of the time, but it might happen sometimes. But yes I do stutter waaaaay more when there are people around. I feel like where no one around a would stutter in 2 or 3 worlds in the conversation, but when I speak to people the stutter becomes more severe and I struggle saying even one sentence without stuttering