Players keep asking what formation we are playing

I would not stop using formations, but I would gradually make the numbers less important than the relationships. A formation is useful for giving players a starting picture. The problem comes when they think 2-3-1 means seven fixed positions that must be occupied throughout the game. I would start using questions such as: Who gives us width here? Who protects the middle? Who can support the player on the ball? What happens if our full-back travels forward? Then occasionally change the starting shape in training while keeping the same principles. Players begin to realise that the football problems remain even when the diagram changes. You can still tell them the formation. There is nothing wrong with an U11 knowing whether they are starting 2-3-1 or another shape. But after that, I would quickly move the conversation onto what the players need to notice once the game starts. The formation tells them where the picture begins. The game tells them where they need to move next.