TL;DR
Kids are surrounded by colours so it is hard for them to distinguish the names of colours from each other e.g. when learning about bears and dogs, a dog and bear aren’t usually in the same place so a child learns a bear is not a dog.
And children learn nouns before colours, but when used prenominally (i.e. “a red balloon” instead of “a balloon that is red”) the child thinks the name of the balloon is red. Children who learned postnominally (i.e. “the balloon is red”) learned their colours much more quickly.
