Answering for deaf above. Deafness is more of a spectrum. Most people classified as deaf or hard of hearing don’t fall into the “cannot hear anything at all, total absence of sound” category. Instead hearing losses occur in ranges. Some people (like my daughter) can’t hear any pitches in the highest ranges. When I play violin for example and I play E string and above, She hears nothing at all. Makes no sound. But she can hear everything below that just fine. Some folks can’t hear tones all over the place and end up hearing more of a muffled noise. Generally speaking, hearing losses aren’t just about volume (though that does play a part!) they’re about whatever pitches/ranges that you have damage or loss in. That’s why the old (and highly offensive) “snap next to someone’s ear” doesn’t work. They may be able to hear that sound at that proximity in that range, but if someone was to shout from a distance or say something at a reasonable volume into a telephone or has a low voice, it’s practically inaudible. There’s also a cognitive processing factor that goes into it. People who have had losses without corrections or aids for a long time may struggle to actually process the sounds they’re hearing since their brains may have actually re-wired to comprehend information via lip reading or other sensory input! Fascinating stuff.