Imagine you found a really cool rock and you want to show your friends. You hold it up and say, "Look what I found!" That's a speech. You're not showing them you; you're showing them the rock.
When it's your turn to talk, your tummy might feel funny and your heart goes thump-thump. That's your body giving you extra go-juice, the same as when you're about to run a race. It feels big inside you, but your friends can't see it. They just see you holding up your rock.
So when it feels scary, look at the rock, not at yourself. Think, "I want them to see this." Then take a big breath, say it slowly, and let them look.