I genuinely feel that 90% of stuttering is bad habits that we have picked up to cope with the stutter itself. If someone asks me to repeat myself, I tense, and my throat closes up, I then try to make sounds and fail. If I am mindful when this is happening, I can relax myself, compose my thoughts, and speak clearly. Bit like driving a car, someone cuts you off, your automatic response might be to honk the horn, swear and drive aggressively etc. You could chill and do something else. I feel that there are scenarios with speaking where I have conditioned myself to panic and behave in an abnormal way. Mindfulness and practice helps me in these situations.