Well it looks like I have alot of company on this topic!
The only way I can describe it is I know what I need to convey, but the words to communicate this are absent, so I just put something together that sounds like something Tarzan would say.
The best one of all time for me was at Wendy's fast food joint, I got up to the counter to order and I got really nervous for some reason. Instead of ordering, I asked "Does big Dave work here? The look on her face was priceless. Anyway, mom grabbed me out on line, totally embarrased, and ordered for us. I felt soooo stupid
One time, I was taking some diet pill over the counter, when I was 12. I started babbling in what seemed to be pig latin or something like that for two weeks, at least until, mom found the pills in my purse. She took me to doctor and the doctor chewed me out bigtime. Soon after a few days my speech was back to normal.
I have never gone completely mute, crosses fingers, but when I get really nervous, I become very shy, dont make eye contact with anything but the floor, and talk in three words at a time.
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All art is a kind of confession, more or less oblique. All artists, if they are to survive, are forced, at last, to tell the whole story; to vomit the anguish up.
-James Baldwin