I think it's abnormal at all. Since I do this all the time. Lol. Sometimes it's a bit hard to actually achieve to have a conversation with someone and it helps me be able to communicate better with other people. I'm not much a social person so I really tend to do this. Or like if I'm scared or worried what might happen if this certain things happen well I tend to converse with myself or have imaginary conversation since I'm a very anxious person. So no I don;'t think it's weird.