Whatever it is it took me like 36 years it has something to do with tension accumulating in the throat especially when using my vocal cords. (Also sometimes when I get stressed my voice starts getting hoarse.) Maybe I hadn't realize this because I'm not sure I'd be called a proper stutterer, but I do become very clumsy when speaking in public, and I notice that everything falls apart. I know it isn't just about the vocal cords, because at those moments I stop both thinking properly and speaking properly. Even my processing when reading drops a lot. In any language. All of which is attenuated as soon as I switch to whispering. Probably the cases vary in part because of differences in the origin of the problem. For some it could be some trauma, etc. Btw, I also have trouble swallowing food.