Apparently a lot of people who have normal hearing are using closed captioning when they watch television.
A few months ago I noticed that several friends (who speak English and aren’t deaf) routinely watch TV and movies with closed captions and subtitles on. I asked about this on Twitter and the resulting thread was fascinating. Turns out many of you watch TV this way for all kinds of different reasons — to follow complex dialog in foreign or otherwise difficult accents, some folks better retain information while reading, keeping the sound down so as not to wake sleeping children in tight living spaces, and lots of people who aren’t deaf find listening difficult for many reasons (some have trouble listening to dialogue when there’s any sort of non-ambient noise in the background).
This all makes sense, and yes, there are definitely some shows and movies where voices are hard to make out clearly. (And yes, I’m in my 50s, so while I don’t qualify as hearing impaired, I have noticed that my hearing is not as good as it was 20 years ago, especially in crowds or loud situations.) I’m surprised I didn’t think of this.