This occurred during my first semester of college two years ago.
There was a girl in my class who never spoke to the teacher. Whenever he asked her questions, she remained silent. I don’t recall her making any sound at all.
One day, the teacher became very frustrated. Believing she was ignoring him and being disrespectful, he yelled, “Hey! Didn’t anyone teach you how to speak?”
She got up, walked to the whiteboard, took his marker, and wrote, “I am mute, you fool.”