I used to talk to myself when I was little, in a sense of actually talk. Not just say semi-random phrases out loud, but actually have a real two-way dialog with myself, complete with responses to each statement. Here's a slightly disturbing example.
I was 5 or 6 at the time. I just got a shot (flu vaccine, maybe, I don't remember) at the school nurse's office in kindergarten. The shot was done, and I walked back to class and sat down. (I remember the "conversation" very clearly, and it's presented here verbatim, except for words in brackets added for clarification.)
Aspie1: (sobbing) "It hurts. That nurse is really mean."
Aspie1: "Don't cry; when we come home, we'll take some medicine [for the pain]."
Aspie1: "It still hurts."
Aspie1: "We're in school; we can't do anything now. We can't put an ice pack [on the injection site], because the band-aid will fall off. Don't cry. The pain will go away from you soon."
The teacher must have heard me talk, because this was during quiet time; you were allowed to read a book if you knew how or play with a silent toy (stuffed animal, Etch-a-Sketch, etc). I was excused from class briefly with a note, when an administrator walked into class and handed it to my teacher. It's really interesting that the teacher didn't say anything to me, given the time the incident took place, year 1988.
Dsbonn, how exactly does your daughter talk to herself? Does she simply tell herself stories (what people usually mean when they say "talk to yourself")? Or does she do the dialog thing like I did?