Yea same mind was quite severe as a child and adolescent and into early university. It’s only become moderate within the last 3 years (I’m 28 now). Techniques that helped me is repeating a phrase or sentence in rhythm and focusing on that rhythm while speaking but but when I encounter a block. I also practice reading out loud to the beat of a metronome for the last 3 months now. That’s helped made blocks less frequent and easier to overcome. I made a post about the self therapy practice, so check that out for details. Another technique I used is that when I block on word, I’d repeated mouth the word without voicing it. I’d work my way up to a whisper and then to full vocalisation. I’d also try to keep the unvoiced muscle movements in a steady rhythm as well. Hope this helps.