I don't think I do this. What happens to me is that words mysteriously disappear from my sentences when I get anxious. Like, "Hi, I'm ___" (when I'm trying to introduce myself) or "Can I get an extra large ___" (when I'm trying to order coffee). I often have to repeat myself. When I'm not anxious I don't have any problem.
It doesn't have anything to do with authority figures, but it's more likely to happen when I'm talking to strangers. Probably because if I'm talking to someone I don't know, I'm more likely to be anxious. Ofc, knowing that it might happen makes talking to people more stress-inducing.
I still often pitch my voice low, out of habit, to make myself sound more masculine. People take me more seriously when I do. But I'm slowly breaking myself of the habit.
Beauty isn't everything. It's the only thing.