My rather reclusive and shy best friend got up in front a large group of people in our permaculture group and gave a flawless presentation and speech on what she did to her farm. Most of these people we did not know, although we were slowly meeting and making new acquaintances.
I watched her in utter amazement, my jaw literally agap!
Afterwards I asked her how she learned to do this. She explained she joined a toastmasters group. And they had to give speeches on a myriad of topics. It was hard at first, but with lots of practice, and a lot of support, she learned how to speak in front of her group. She said everyone was in the same boat, they were all working toward same goal, and it worked!
I questioned her closely. No one new dropped out. She was a member of the group for several years until she remarried and moved away. If there is a group near you, I'd try it out, a least once.