There are a few films where this is the case. Without researching it one that comes to mind is IT, the protagonist has a noticeable stutter, he gets mocked by some bullies. What I find hilarious is that usually netflix or other subscription services will have *stutters* in subtitles for pretty much all dialect when a character slightly hesitates or repeats syllables/words. Usually they don't stutter but I suppose the subtitles have to accurately include everything.