They criticize peers and teachers freely.
Young children tend to have high standards for themselves and others. It’s not uncommon for a third grader to complain that his teacher is mean or that a classmate is stupid. This can also be a time when siblings fight.
What you should do: When your child has a critical opinion of someone, don’t automatically scold him for it. Instead, open a conversation about why he feels that way. It’s a good intellectual exercise for him to explain his opinion thoroughly.