Have you tried progressive relaxation? You tense the speech related muscles for 5 seconds, recognize how it feels, and release. Practice it every day. You'll be better able to recognize when you get tense. A lot of time, PWS hold their breath before they speak. Don't do this, it creates tension. When you go up to someone to talk to them, breathe out, breathe in, let out a puff of air, speak. Practicing diaphragmatic breathing can help you to relax. Drop your shoulders, breathe in for 2 seconds, out for 4. Repeat.