My DS5 does this. I've never seen another kid do it so I'll be watching this thread.
My son was always a talker (he started at about seven months) but we started to really notice this at about 2.5 years old. At the time he was fascinated by pinball machines and marble mazes and he would walk around and tell a story tracing the path of the ball through the pinball machine/maze in his imagination. He would go on for half an hour without stopping. When he turned three he became obsessed with Rube Goldberg machines and turned to describing them. Then he moved on to motors and the internal compontents. . and then to elements and describing the contraptions he wants to build and what materials he would use. He talks a lot and gets very carried away with his stories. My husband and I feel overwhelmed and overstimulated by the constant talking.
We think the talking is a creative outlet and also a form of self-regulation. My son is sensitive to noise and when we are in a noisy place, he often paces and starts telling his stories. He also did it a lot after his baby brother was born, especially when the baby was crying or unhappy.
Last year, our son's preschool teachers told us that he talks incessantly at school, that he doesn't seem to care if anybody is listening and that he talks over the heads of the kids and teachers (that is, he talks about chemistry and physics so nobody really understands what he's talking about). We had my son evaluated by a psychologist and that's how we learned that he is gifted. We knew he was bright and quirky but we didn't realize that he would have such a hard time fitting in at school.
I'm happy to report that the talking has decreased and become more appropriate in the last few months. I'm not sure if my son had a developmental spurt or is just more relaxed but he no longer talks incessantly. He's also getting better about not monopolizing conversations. We've had him in a social skills playgroup for about six months so that may have made a difference, too.
My parents tell me that I talked incessantly when I was a child, too. I still like to talk but I've learned to let others take a turn, too!
