When “S” is in the beginning or the end of the word, we usually pronounce it as “S.” Beginning of words: see sip same said sat suit soot soak soft sock soy sour sun sir sign sale/sail
It is more challenging to determine the correct pronunciation when “s” appears in the middle or endings of words.
Ending of words:
“S” Pronounced as “S” mess mass class bass hiss lease dose moose/mousse boss increase decrease close (adjective) case endorse worse purse loose gas horse crease nurse license hearse terse abuse (noun) recluse refuse (noun) Exceptions: hose, fuse, use, lose, close (verb), surprise, please, his, was, does, is, appease, phase, amuse, cruise, abuse (verb), refuse Middle of Words: “S” Pronounced as “Z” raisin season reason disease miserly easel diesel weasel rising closing laser basil/basal doesn't wasn't isn't commiserate hesitate design present causal phrasal preside
Exceptions: dosing, casing, endorsing, increasing, decreasing, bison, worsen, person, fuselage “S” Pronounced as /ʒ/or “zh” measure pleasure fusion vision visual casual lesion version leisure incision provision exclusion
“SS” Pronounced as “S” lesson classical fossil guessing depressed assign missile message possessive assess
"SS" Pronounced as "Z" scissors possess “SS” Pronounced as“/ʃ/ or “SH” tissue mission fissure issue possession “S” pronounced as“S” courtesy curtsy crisis aside
It certainly appears that in the middle of words, “S” is usually pronounced as something other than “S.” So, unfortunately, we must rely on memorizing the patterns that you see above.
If you find more rules or more exceptions, please let us know!