Teachers are sneaky about finding ways to get students familiar with talking in front of the class.
In kindergarten, first grade and maybe even second grade, it’s disguised as show and tell. You’re bringing in an item from home that you love and talking about it. Early on, teachers emphasize the importance of sharing what you love.
That’s public speaking in its purest form. Eye contact isn’t evaluated as much and neither is the smoothness of your delivery. You’re just sharing to the best of your ability.
So those are good building blocks that progress through each grade level.