The key thing here is reflection. You can look at your speech again and ask: am I more anxious about saying something I don’t like, or about this? I also was a slow-speaker, which in my case was actually anxious-speaker. But at some point I said “f… it” cause no one really cares deeply about the perfect form of a fine structure of your message. Literally anything is better than your awkward stumbling.

Be wrong and say stupid things. You will be corrected or correct yourself. Accept the correction and move on. If you feel very wrong, turn it into a question? Instead of feeding back to anxiety you’ll feed back to speech.