You are excluded at school because you are hearing impaired. They never try to get closer, they even cover their lips when you are nearby, preventing you from being able to participate.

There was pair work in the class, everyone joined someone except you, until a boy appeared. He wore a mask, but that wasn't a problem, after all, he knew sign language.

— Hello, how are you?

The boy says in ASL, a little awkwardly, but he's clearly making an effort to communicate with you.