This. As a severely hearing-impaired individual, context is EVERYTHING in a conversation. Or, like, 95%. In all but the best environments, I'm not actually hearing what you're saying, I'm pattern matching your garbled sounds to the closet logical words my brain can think of. The narrower the context, the better and faster I can do this.
This is why, for example, I don't answer unexpected phone calls. If I don't know the initial context of the call, the first minute is going to be very confusing for both parties.
The human brain is remarkably good at filling in the blanks.
I rely on context, plus lip-reading, plus the sounds I do hear to figure out the rest.
For context - I'm not severely hearing impaired - I only have a mild-to-moderate loss in both ears, but it's enough to hamper me in normal conversations, particularly in group settings or noisy environments. I use Siemens hearing aids at work, at church etc. - basically, anything that's not 1:1, or where I can't easily ask them to repeat things constantly.
This is why, for example, I don't answer unexpected phone calls. If I don't know the initial context of the call, the first minute is going to be very confusing for both parties.