That's a really interesting observation. I've got hearing damage in the high frequencies, so I'm incapable of hearing the difference between an 'f' and an 's'.

That's a really interesting observation. I've got hearing damage in the high frequencies, so I'm incapable of hearing the difference between an 'f' and an 's'. Fir and Sir sound identical to me, and I can only infer from context! However, I can -speak- them due to the difference in mouth and tongue placement + av therapy.