I have a weekly work meeting and I experience this too. I practice before the meeting and it's all great until it's my turn to talk. I've honestly learned to say screw it and embrace it, I say Uhms like every second word. I'm not so hard on myself anymore. Slowing down my rate of speech and using my stretches and easy onsets are helpful, but sometimes I feel like I'm talking Uber slow (at turtle speed) even though I'm not and sometimes I just want to be done talking.