Is it "S" or "Z"?



A common conundrum for many non-native English speakers is how to pronounce “s” in a word. Is it pronounced “s” as it appears or “z”? How do we know? Can one differentiate “diseased” from “deceased”? If not, the message can certainly be misinterpreted, e.g., “The patient is diseased/deceased.” So, in an attempt to clarify some of the English patterns and make some sense to the idiosyncrasies of American English, we organized some patterns or RULES for the pronunciation of “s”.Of course, there are exceptions, and we welcome your feedback and any patterns that you have observed that may be helpful to English language learners.

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!