We're lucky regarding this, dd's private Catholic school encourages the children from Kindy on to get up in front of a group and learn to speak with confidence. This has never been a problem for her, so she's lucky she doesn't struggle with it. She's even volunteered to get up in front of the entire school to speak! I could never have done that at her age (she's 9yo now).
The children have several opportunities throughout the school year to speak in front of others and it's one of our favorite things about this school.