Autism and speaking

As someone on the spectrum, I often dislike the sound of my own voice. Half because of self deprecation, half because I often find myself blabbering on for too long and it begins to sound like nails on a chalkboard.

Considering myself as a "quiet autistic," I don't speak much at all, but when I do- it feels wrong? I find myself so anxious when talking that my jaw starts to fill stiff and my throat closes up. It causes minor speech impediments like pronouncing words wrong, replacing my "Rs" with "Ws," and putting heavy emphasis on the letter "I." Not to mention my "autistic accent."  

I've just met so many autistic people that struggle with the opposite of my problem, talking too much and not being able to stop, but I find myself not being able to speak much at all.

Is this common?