For me, I discovered speech blocks happened because of my fear to actually stutter. A "normal" stutter will go like "st-st-st-s-ss-stutter" or "b-b-b-b-b-b-bread". Me fearing that others could actually hear me stutter like that, actually kicked in a sort of fight, flight or freeze response. Mainly the freeze resulting in the classic block. "Bbbbbbbbbbbbbbbbb" (for bread) with the feeling of being choked by your own throat. The moment I decided to let myself stutter "authentically", meaning, allowing myself to stutter without fighting it, I stopped blocking almost entirely. Blocking, for me at least, was a panic response (freeze) - being afraid that others might hear me stutter the "authentic unedited way". As in "s-s-s-s-st-st-st-st-stutter". As in the classical repetitive repeating of letters or syllables. I absolutely hated and feared the idea of another person hearing me stutter that way. Now, I don't really care too much anymore. Blocks don't happen anymore, because I allow myself to stutter without fighting the stutter. And because I allow myself to stutter , I stutter way way less then before. Stuttered since I was about 7yo. Now 33yo. Hope this helps.