As a child I was taught by my mother that the letter S was enunciated by blowing air through the teeth and placing the tongue behind the teeth (without touching) to create the clean hiss sound of S. When I was taught, the distinction was made that there was no involvement from the lips, in fact, they were to be opened to reveal the teeth.
Recently I have noticed many people enunciating the ‘S’ sound by pursing their lips in order to create the sound. It ends up being enunciated as ‘Sf’.
A) What would this sound be called? By touching the teeth with the tongue you can make a sound as ‘sth’ or ‘th’. By pulling the tongue to the back or bottom of the mouth the ‘sh’ sound is made. The former is refered to as a lisp and the latter is refered to as a slur when attempting to enunciate an ‘S’ sound.
B) Is this something that is/was being taught? I understand the narrow distinction and difficulty for some people to learn the difference, or be able to make the distinction (especially as kids).
C) Given the sorts of different sounds that different languages/cultures/dialects use, that the ‘S’ sound was (almost) universal and enunciated the same way. Is this not true?