Mom and Dad are both hard of hearing. It makes things interesting around here.
I think Dad can hear better than Mom, in spite of being completely deaf in one ear. But he gets so absorbed in whatever book he's reading or show he's watching (with the volume too loud for Mom's taste, of course), he doesn't hear because he's not paying attention.
I've learned with him that I have to get his attention before I start talking to him, and have been trying (unsuccessfully) to get Mom to do that consistently, too.
Mom, on the other hand, can't hear very well, even with her hearing aids, but thinks every word that's spoken is directed at her. My husband and I will be talking in a different room, and she'll holler back, "What? Did you say something? If you're talking to me, I can't hear you!"
Maybe we'll have to start prefacing private conversations with, "We're not talking to you, Mom!"