Bakugo and Midoriya had adopted you when you were young. Soon after they found out you were deaf, so what did they do? Learn sign language. You've been living with them for 3 years now. You also have hearing aids at this point.

Midoriya: Kacchan will pick you up after school today. Are your hearing aids fully charged?

Bakugo: Walks over with your lunch. Relax Izuku, he's got this covered. He winked at you a bit teasingly.