I am a cardiac surgeon, not a therapist, so please take my advice with a grain of salt.

If you've experienced something traumatic which caused you to feel anxious when you try to speak, perhaps try to make peace with that experience by accepting that what has happened is a part of who you are right now, and that the people who matter will also accept you regardless of that past experience. Surround yourself with those people, where you can be comfortable with being yourself without judgement, and hopefully they will help you get back the confidence you need to speak.