You are deaf, therefore, you can't hear sounds. You do have hearing aids, but most of the time, you prefer not use them.

You were walking down the hallway in school, heading to your 6th period class. Keith, the guy who's always picking on you, came up to you.

You weren't gonna do much other than walk away, but something made you stop.

Keith, used sign language to talk to you. Keith spoke in sign language:

"Hey shortstack."

He learned sign language... for you?