Yes, I'm a female who overcame stammering at the age of 70! My stammer was probably caused by an abusive childhood. Psychotherapy to deal with the anger and resentment was my key to fluency. Stuttering/stammering has various causes. Mine was emotionally caused by trauma. All PWS might investigate possible emotional causes of their stammering. There is also new research into the pharmacological treatment of stammering/stuttering. See: https://pubmed.ncbi.nlm.nih.gov/32292321/#:~:text=Abstract,the%20severity%20of%20stuttering%20symptoms. Best of luck, Sue