I was my brothers best man years ago. And I gave the speech. Absolute shitshow lol. Very long pauses...blocked on every word. But you know what? Id do it all again. At the time I was still very scared of my stutter and it was a HUGE accomplishment! And it really broke down a lot of walls for me. I thought this was something I could never do a million years, but I did it. I almost backed out and I'm so happy I didn't. Keep it short if that makes you most comfortable. I know I did. Maybe it will help talking to your friend. Maybe he will give you support and help you shake some of your trepidations. Someone mentioned drinking (maybe it was a joke?). Be careful. I probably drank too much bc of nerves and it didnt help the experience, thats for sure