That’s an interesting point. I think I’m the same way. When I’m explaining something on a professional level I hardly have any speech impediments, while I do notice then more when I’m just messing around. I think it’s because I do take the time to breathe and speak properly with clients. But when I’m just casually talking it’s less structured and it’s almost as though my brain is trying to spit out everything at the same time so I get flustered.