This was a late 80s american movie, but I think it was set in the 50s. There's a scene where a boy asks his teacher if he can go the bathroom. The teacher says, "yes you can, but you may not." I think the boy misunderstood and got up to go. The boy gets in enough trouble that his grandpa has to come into school. The grandpa is an immigrant that speaks with an accent and expresses frustration about the English language. He gets upset with the teacher for telling the grandson he can and then he cant do something.