Some tips: Talk to yourself. Read outloud. Take deep breath and start talking on exhaling. Meditate. Talk more to people you are comfortable with. For me, my brain can tell if I'm gonna stutter ahead of time as I talk. So I take a pause before I know I will stutter, take a breath or restart. Sometimes at home, I stutter on purpose just to see how my mouth moves or what my brain does and then I kinda slowly process it and correct myself. This way it's like my brain memorizes how to move my mouth (muscle memory) properly when I talk. I write down words or letters I struggle with and then try to find some text that has a bunch of them, and then read outloud. Meditation can calm your nerves down. So next time when you get very excited or nervous, it will be easier to control it. Those are the tips that help me with my speech. Hope some of them will help you too.