Two of my sisters used to stutter very badly (they sometimes still stutter but not nearly as bad as before) and my father said that when he was a child he had severe stuttering. Sometimes you can hear when he is about to stutter and he immediately changes the word, he doesn't do it often though, usually he speaks fluently. When I was in elementary school there was a boy on my class who also stuttered but not as bad that I did. People used to mock my speech problems but said nothing to his. Not saying that they should have bullied him too it's just weird that his stuttering wasn't a problem for them but mine was 🤷‍♀️