They make great points, I would be interested on what else you pick up during the rest of the program. The jaw angle theory would explain why stuttering is typically associated with specific sounds. The sounds can very person to person but are pretty consistent once you identify them. The skull resonance is interesting too. I know I am usually tense when anxious, that could explain why vibrations travel differently. Especially if we are somehow physically pre-destined to have issues interpreting vibrations.