Breaking old habits / thought patterns / avoidance behaviours will take time. You took the first step on putting in the time and effort of working on your speech. Now it's emotional trauma / past memories you have to slowly work at. I guess you can start doing things you've never done before, slowly going out of your comfort zone. Also maybe doing some meditation / breathe work alongside that can help coupled with some therapy. It's up you how you wanna deal with it.