The /s/ and /z/ sounds are both producing in the same way differing only in voicing (vibration of the vocal folds) with the /s/ being unvoiced (with your voice turned off) and the /z/ being voiced (with your voice turned on). The /s/ sound may be spelled with multiple letters several different ways including:
s as in sat
c as in city
sc as in science
ss as in class
x as in box
Additionally, the /s/ and /z/ sounds are also grammatical markers. Plurals, possessives and noun-verb agreement all require the use of the /s/ and /z/ sound. For example:
She walks (noun-verb agreement)
Two cats and two dogs (plurals)
Mom’s car (possessives)
s as in sat
c as in city
sc as in science
ss as in class
x as in box
Additionally, the /s/ and /z/ sounds are also grammatical markers. Plurals, possessives and noun-verb agreement all require the use of the /s/ and /z/ sound. For example:
She walks (noun-verb agreement)
Two cats and two dogs (plurals)
Mom’s car (possessives)