levels of deaf awareness.
My husband is very hard of hearing, even with aids. (age related, not life-long)
What always surprises me is his lack of awareness that anyone else may be similar.
So if we drive or cycle (with a cheery hello) towards someone with their back to us, and they don't move over, it doesn't occur to him that they might just not have heard us.
Same if someone doesn't contribute much to a conversation, or reply to a greeting, even though he often doesn't himself.
With prompting, he is getting more aware....