I would’nt have been able to understand that old man had I not met the people he described. One is a senior officer during my time in the military and another my university friend. Both stutter severely but are not insecure about it. I stutter way less and block more but the insecurity shows. I’m trying to work on it. I think one method is after u are over ur word, don’t change ur tone and what not. Just pretend like nothing happened. Don’t even acknowledge the “cock up”.