As of when I'm writing this I haven't spoken to anyone in over an hour, and my disorders are autism, ADD, and GAD. I am currently at a family reunion, so that's really saying something. I rarely have moments where I actually can't speak, although I regularly just don't want to speak and I prefer typing over speaking.
My experience aside, this is indeed a rather common autism thing.
_________________
Also known as MarsMatter.
Diagnosed with Asperger's, ADD, and Generalized Anxiety Disorder in 2004.
In denial that it was a problem until early 2016.
Deviant Art