Since you’re trying to write a character, I think it’s very important to try to understand the mind of a stutterer. You may have specific situations in mind that you want to write into your story, but you’ll do much better when you have a more specific understanding of who your character is. Stuttering is a disability that has to do with speech. If I need to give a comparison, I would compare it with bad eyesight. You can still see, but depending on the severity you have trouble telling what exactly something is. If you’re reading a book you can move it closer to your face, but other than that or squinting your eyes there’s not much you can do about it. You just can’t see well. Much so with stuttering. Many stutterers have the same frustration: you know what a word is, you want to say it, but sometimes you simply can’t. You can try the tricks they teach you in therapy but that only brings you so far. Imagine if someone shows you a circle and a triangle and asks you to name them, but he does so from 20 meters away. You genuinely can’t see the shapes. You get frustrated because you’re trying your best, yet they are laughing and ridiculing you for not being able to give a good answer. No one else has trouble naming the shapes except you. And only after a really long intense stare can you tell the shapes apart. It’s because of that awkward feeling that some prefer to just move on with the conversation. It’s very important for your character to understand this. Stuttering is not just like missing a leg, something that others can see and understand and that you can learn to deal with if given the right tools, because the right tools don’t exist (yet). Stutterers often have to face misunderstanding, people not knowing what to do or how to react to a stutter. This can build frustration within and a feeling of being lonely or ostracized by something you were born with. If you understand how important speech is for humans, you’d be able to get an idea of how cruel and downright brutal it can be to be handicapped in that area.