2 thoughts...
1. some times it can be a sign of insecurity
2. when my T does it I know that she is really in the moment, experiencing things with me and "forgot" to take a step back into "her" and compose her thoughts before speaking. If she catches herself she will stop, sit back, close her eyes and pull the thoughts together then move on coherently. She has a PhD, is a professor and I would guess her IQ to be in the 160+ range.