First of all, I drive shift stick for the past 5 years after I switched over from automatic.
It is called that way in America, we call it "manual" down her ein AUstralia too.
There is no common snese in there, mate. Deaf people can drive manual, doesn't HAVE to have hearing. Just takes a bit to learn the shift stick.
Nope, you don't need your hearing to listen to the transmission, just like what Doug said, you can feel it, if it break down, driving the stick, the stick has vibrations you can feel it if the tranmission ends up having serious issues.
My '98 festiva doesn't have tacho, and it is manual. Been driving that car for three years and I got used to know when it is time to change.
There is so many different ways to know when you need to change gears, you don't need your hearing at all. Not at all. You can feel it, and it also dpeends on the speed you are at. You know when you change. When you learn, you'll know what I mean.
Even my car is new, and has tacho, and can't be bothered to check my tacho, just that I learnt how this new car runs.