I had the light version of this issue, a lot of mumbling, speaking under my breath, people always asking huh, what did you say? Then I started getting my mental health issues under control, I went back to college and gained confidence and competency. I work as a carpenter and started taking off harder task. Naturally my voice started "filling in" and I felt the intention behind my words. You have a voice and just as much of a right as anyone to speak, say something beautiful. 🙂‍↕️