For sure! When I'm tired.. it's a dice throw... I've found that learning muscle relaxation exercises can help.. How? example: https://www.verywellmind.com/progressive-muscle-relaxation-pmr-2584097 It's an exercise of tightening and loosening muscles, you learn to relax them when you want to. You practice once or twice a day. You learn to recognize when your muscles are tense, then you try to remember what they feel like when they're relaxed.. and relax to that state. You really need to learn to "check in" with yourself several times a day. Now - then you are talking, about to talk.. etc.. relax. You scan for tension and try to release. Now .. why? If you "hard block" your body is likely tightening and tensing. That is the case for me. So you wind up "fighting" your own muscles to continue talking and stuttering and it's totally exhausting. I've always struggled with "just relaxing" - but when I a able to do it - it makes a big difference.