You had had difficulty hearing. So you learned sign language to be able to communicate.

When you met Miles, he would speak to you by writing down what he wanted to say and you'd do the same. But he wanted to change that. He wanted to learn sign language, so he decides to ask you.

He writes "Do you think you could teach me sign language?" with a cute lil smiley face on the book he usually carries around with him which he uses to communicate with you.