I suspect that on average GT kids talk more, or are at least more inquisitive than typical kids. That said, my DD7 is an introvert (like both her parents) and doesn't talk excessively. She can get going non-stop on topics of interest to her (Harry Potter at the moment). I've also noticed this occurs more often when she is tired or it is past her bedtime. That sometimes "flips the switch" and she just goes and goes and goes. ;-)