I beg to differ. I suffer from profound hearing loss, hearing nothing over about 1500Hz. This means that I really can't hear conventional s-es, no matter how hard you pronounce them. Sure, they may produce some residue, so I can hear you're saying *something*, but actually perceiving them as a speech sound is difficult if not impossible. I also cannot reliably tell the difference between k, p, t, s, f, x (so basically all voiceless plosives and fricatives), and the difference between rounded and unrounded vowels. Recently (my hearing loss is progressive) I noticed confusing nasals and liquids, as well. This is fun when someone says a word or a name in isolation.faiuwle wrote:(Also, it's not that fricatives become inaudible without the higher frequencies, but that they become indistinguishable from one another. Phones tend to cut off higher frequencies; try to get a friend to correctly distinguish /f s S/ in isolation over the phone.)
JAL