Speech therapists working with dysfluency call these secondary behaviors or physical comorbidities, because they are a separate thing from the stutter itself. People develop these habits over time as they work like temporary fixes to surprise your brain out of a loop, or so goes the theory. They are generally a temporary patch over the stutter that your brain will overcome and adapt to, leading to the behavior having to become more exaggerated to have any effect, and it can get totally out of hand. But many people who stutter accumulate at least a little bit of this. Subtle behaviors can be tension or small movements of the hands, shoulders, face, and eyes. Large ones can eventually turn into tics, jerking movements, or unusual noises. Those become so automatic, and appear so uncomfortable and distracting, that they're more of a barrier to a conversation than the stutter itself, and they're the first thing to undo if you go to therapy to learn fluency management techniques.