I think that in my case anyway its just intense ptsd related & has been a part of me for so long its created a probably unbreakable stronghold in my brain. From being brutally embarrassed & abused many times as a child its 2nd nature to tense up & get a adrenaline spike when I talk to people...I can communicate & conversate fine tho despite the stuttering. And what's funny to me is that I can go to a bar and ask for specific beers absolutely fluent or say certain word fluently. But for some reason I can't say my damn name to save my life 😂...that's how I know it's psychological & ptsd induced from being abused as a kid for tripping up on my name a few times...no wonder why practicing speech therapy alone doesn't do literal jack shit to help, because I can be normal & fluent by myself but as soon as I'm around ppl I don't know I tense up & get adrenaline no matter how many anti anxiety supps I take or meditation I do before hand. Maybe every stutter is different. But for the most part I think we are so used to having anxiety that we don't even feel or recognize it anymore. Idk 100% but it feels like a low grade chronic ptsd response to me.