Hecc!! I forgot to mention!! In regards to the last headcanon, sign language is also a thing!!

Mitsuki and Masaru were informed of Bakugou's hearing loss when he was about nine, so they began teaching him sign language just in case. By the time he was eleven, he was fluent.

Once Kirishima found out about the whole partially deaf thing, he made an effort to learn at least a bit of sign language just for Bakugou. Simple phrases for various situations, ones such as "what do you want to eat", "how are you feeling", even "i love you" just because he felt it was necessary, etc., etc. Of course Bakugou has told him time and time again he doesn't need to do that for him but Kiri's a softy who loves his boyfriend. He uses it frequently if he wants to get a question or statement across without any struggle.

Also!! If you're wondering how he learns sign language, Present Mic is also fluent! Growing up, his parents quickly grew deaf because of his quirk, and he felt awful. He put in a significant effort to learn sign language along with his parents to communicate with them, and became fluent very fast! So, if asked, he'll gladly teach a student any phrases or words they want to know!!

pff that was headcanon and a half
y'all i fuckin love deaf bakugou ok i'm sorry!!
i'll stop!!