It's called glossophobia!
Lots of people are terrified of public speaking and I used to be too. I'm still scared of it: my chest gets tight and my heart pounds for the 45 minutes before a talk, and the week before is full of moments where I realise it's getting close and freak out a little. Someone just now tweeted that I'm speaking at QCon soon and I honestly said "AAAGH" out loud to my empty living room. Speaking is scary! But I still do talks.
Our internal work speaker group asked me to do a talk about conference speaking last week. I covered a bunch of things around writing an abstract, making slides and so on, but the thing that really seemed to resonate with people was admitting that I'm still scared. I shared how I worked up to doing it anyway and a bunch of people told me afterwards that that was useful, so I'll share it here too.
I have two approaches for doing things that scare me, illustrated here:
One is to play a horrible trick on my distant future self, and sign her up for something awful. I've used this a bunch to make myself have difficult conversations, or to travel on my own to places where I don't speak the language. The key is, you need to pick a time that's far enough in the future that your brain doesn't think of that person as really you. (I think this kind of mental gymnastics is the only way anybody ever decides to give birth.) Ideally you rig it so not doing the thing will feel worse than doing it. If your name's on a conference schedule, getting out of talking is a whole lot of socially awkward, so future-you has an incentive to figure out how to do it.
The second one is kinder! It's to keep taking small steps and doing things that are just a little scary. If you're petrified of speaking in front of other people, you don't have to jump all the way to a conference talk as your first step. You can start by presenting something to your own team, and do that a few times until it's only mildly uncomfortable and not actually nightmarish. From there, maybe you'll work up to presenting to adjacent teams, or to customers, increasing the size and pressure of the audience and content you're comfortable with. What's good is that you get skills every step of the way; it's useful to be able to get more comfortable at presenting information to your team, whether you want to speak at conferences or not.
For me, some of the small steps were still a terrifying diving board. I used to be so frightened of public speaking that even taking my turn to share a status update in a meeting was scary. This felt like it was becoming a problem, so I signed my future self up for a TEFL class: learning how to teach english as a second language. The coursework included teaching a bunch of practice classes, initially to fellow trainee teachers, but then to real language learners who had paid to be there.
Scary? Very. Also intensive: it was a 115 hour class, over four weeks, which I fit in around my full time job. Looking back, I find it astounding that this was the easiest way I could imagine to get past my terror of standing up in front of other people.
Those practice classes were traumatic. I freaked out for days beforehand. I cried in the bathroom. I had trouble breathing. But I did them! (And I got a B on the course, though I think my grammar nerdery brought up my grade.)
After that, small presentations were a bit easier. After a bunch of those, big presentations became doable. After some of those, meetups were possible. And so on. None of the steps after that ever felt as impossibly awful as that initial TEFL class. I'm currently working on the step at the top there: speaking without extensive speaker notes. I've only done that once so far (presenting this very talk, in fact! It was so scary!) and I'm going to need to do it a few more times before I feel at all comfortable with it.
So, for people who are scared of public speaking, I really recommend taking a step, any step, towards it. And if you're a manager or a team lead, give people around you opportunities to do the same. If you're going to speak at something and it's within your comfort zone, see if there's someone else who could do it and be stretched a little. Even if they'll communicate the information less well than you would have, you can only make people learn to be great if you give them the space to be just ok. Then (as Michael Lopp said at The Lead Dev New York this year), you get to coach them from a B to an A.
The whole talk is at https://www.slideshare.net/TanyaReilly/a-talk-about-talking if you want to read me rant about how Arial is the worst thing you can do to your slide deck :-)