That's dumb. The majority of the conversational vocal scale is below 500 Hz, no wonder it sounds like mumbling. Most people aside from trained stage actors and some radio/television broadcasters do not enunciate very well at all. Lazy, sloppy, monotone voices are difficult to understand, but that's what people give us by and large. Some of the worst are the ones from the orthodontics generations, starting in the 1980s, where braces and fixtures cramped kids teeth into their mouths so much that there is no room for their tongues to move and they speak like they have a mouth full of gravy. Another side effect of those generations is being television-educated instead of reading-educated which results in an absolute lack of vocal punctuation.
More hearing/non-hearing stuff:
From 150 Hz to 2000 Hz my hearing is flat at 25 db, then it picks up to 35 db at 3500 Hz and has a steady decline to 25 db at 8000 Hz. I have pillows covering my ears and everyone whispers.
The consonants B, C, D, E and P are indistinguishable from one another.
Without my aids I cannot hear crickets.
Try as I might, understanding an English as a second language speaker is almost impossible. Not only do they talk with a mouth full of gravy, there's mashed potatoes in there, too.
