I might do this for the other two as well but I'm not sure yet, so for now I'm just gonna upload this one since I haven't uploaded anything for the villains since the last five chapters.

Tomura Shigaraki:

Sometimes he's patient while you sign, other times not. If someone mocks you or insults you, he's sure to make sure they can't hear or speak either, chuckling that they can now experience how hard your life is first-hand.

Kurogiri:

He will be patient, watching as you sign him stuff. He knows sign language so he understands you well. If you are deaf, he feels bad that he can't sign anything back to you since he doesn't have hands, nor does he have a mouth so you can't read his lips. So he will carry around a small notebook with a pen in his pocket so he pull it out when you want to talk and write everything he says down so you can understand him.

Dabi:

If you are deaf, he will sometimes just use his flames to spell out words so you can read them and understand what he's trying to tell you. If you are mute and trying to tell him something by using your hands, he will just wait and let you take your time. When you get nervous, feeling as if you are wasting his time, he will pat your head to tell you it's fine and he can wait so take your time.

Himiko Toga:

She found it annoying that you both couldn't communicate well so she picked up a sign language book and learned a few words. At first she was bored of reading it but when she realized that way you can both talk and nobody will know what you two are saying, she became excited to learn it. So sometimes, you both will sit in a crowded room and she will sign some words to you, being her usual weird self without anyone knowing.