A lot of people speak in disjointed thoughts and sentences, they start an idea, stop it in the middle, then start another idea then stop it and start another one. Notice, when you do that, people really get uncomfortable because they are trying to keep up. What you are doing is trying to manage your anxiety because your brain is ready for the information sooner than your mouth can get to it. So, simply slow down, deliberately slow down and complete each thought. When you do that, you are in command and the listener finds it easier to follow you.