That is what I have been asking myself for years. I don’t have a stutter (most of the time) but I have what’s called cluttering, so all my words come out in one big jumble. People say “why don’t you just slow down?” Thanks! Why didn’t I think of that? It would have saved me years of embarrassment and torment! But for real, my speech therapist taught me to elongate vowels. It helps a bit, but when I get flustered, it still comes out in a mess. I have to force myself to stop, take a deep breathe and focus on the exact thing I’m trying to say, then say it. It’s still embarrassing, because I’m staring at the person for about 5 seconds while I compose myself, but it’s better than being asked “what” for the 4th time.