There are significantly more people with “anxiety disorders” on a global scale, than stutterers. They don’t stutter. So no, anxiety doesn’t “cause” stuttering. Stats: According to the World Health Organization (WHO), anxiety disorders affect about 359 million people worldwide (as of 2021). Approximately 4.4%. Only 1% of the global population stutter. Approx 80 million. I guess these numbers are based on “reported cases”, but you can see the big differences.