I saw it mentioned already, but Lee Lovett's book elaborate on this idea. Going off of memory, he explained it as your brain has memories of stuttering, so it develops an anticipation of stuttering, and the anticipation's anxiety triggers a stutter. I know in my case, anytime I have mentally prepared what to say, I stutter. Like you said, reading allowed, I stutter. I straight up just don't try reciting jokes anymore because it's another thing where I know what I'm going to be saying. The number one thing for me since I became aware of it is spontaneity. I try not to think of a single thing before I say it. As long as I'm constantly reacting, and not initiating a thought, I have no trouble. I high school if I had to do a presentation I quit trying to read what I'd write, and just try to memorize facts I needed, and give the speech off the top of my head. Lee Lovett talks a lot about his crutches for stuttering, and a lot are just trying to stay one step ahead of your own mind. If you know something is likely to make you stutter, like your name, you try to switch it up at the last second. One example I remember he gave was saying your last name first, opposed to first name first. Or swap the word you anticipate the stutter on with a similar word. I really try to expand my personal dictionary for that reason, so it's easier to substitute a word. Ive really become aware lately that I often have little to no internal dialog because of how Ive tried to not prepare thoughts for over a decade now.