Today: adult with no problems doing public speaking in front of hundreds.
What fixed me: more public speaking and not having the option of avoiding the task.
I still don't really like it but I also realised that dragons don't appear from portals and eat you immediately if you do it.
My missus is much like I was but she never got through it, she finds it fascinating that I can.
What also helped me is being so knowledgeable about the topic that I didn't need to prepare the presentation much (except for the slides and the general plan). When you know what you have to talk about, it becomes a lot more natural and relaxed for me.
I would be a lot more stressed if I had to learn a presentation by heart and it would probably be a robotic delivery.
So I did quite a few "surprise" presentations, with very light prepared material and a topic I cared about. Got me the practice I needed and I learned not to get "stuck" as if I forgot the next sentence. The presentation always flows!
Now, I have a talk at a major conference, and I'm afraid this won't work there, so I'll prepare my talk better this time, maybe even have speaker notes!
1. Actually being very knowledgeable about the subject in question, to the extent that I can offer facts or well-reasoned opinion on the topic on essentially any reasonable question. In other words, not being a junior high school student asked to do a 15 minute speech on a topic drawn from a hat.
2. Not having the idea that the audience expects a correct and immediate answer to every possible question.
3. Not doing every single speech literally in front of 15% of my entire peer group, including all my friends, all the people I admired, and all the people who treated me poorly.
I still hate doing Zoom calls without slides or a screen to share because I can't stand having 20 people staring intently at me. It's just distracting. But otherwise I have no problem at all talking for hours on a topic I know well.
Yup, that's the cure. Worked for me, too.
The teacher started off with "you're all going to look like idiots and embarrass yourselves, and you'll have to get over it. Best you do it here now rather than in front of coworkers in a few years. She gave us skills and techniques that I still rely on today, and most importantly, the opportunity to practice.
I was a introverted going in to college, and that class didn't turn my into an extroverted social butterfly in 4 months. However, I have never been paralyzed with fear when required to talk in front of a crowd, and that has been invaluable in my career.
Like every time I hear "Oh I'm just not a math person." It's not that I expect everyone to like math because I do, not at all. But I do expect people to not artificially limit themselves. :/