We often put an -s at the end of a noun to make it plural or possessive, or at the end of a verb to make it third person singular.

But in many cases (perhaps in most cases) that -s is pronounced as -z. Thus for example falls is not pronounced like false, man's is not pronounced like manse, etc.

Two questions:

1. Is there some rule for when the final -s is pronounced as -s , and when it is pronounced as -z?
2. How did the spelling evolve so that we don't spell with a final -z, in the cases where that is the pronunciation?

It's a phonological rule in English that the ending -s for the plural of nouns and the unrelated ending for the third person singular indicative active of verbs is pronounced /z/ when it follows a voiced consonant. For ecample, /p/, /t/, and /k/ are voiceless, but /b/, /d/, and /g/ are voiced. The rule applies to phonology and not spelling. There's another choice, and that is if the noun (or verb) to which the suffix is being added ends in a fricative or affricative, then an epenthetic schwa is inserted (as in church, churches. For example, top, tops, pot, pots, dock, docks have unvoiced /s/. OTOH, fob, fobs, pod, pods, lug, lugs, all have voiced /z/. It's pretty common as languages go; it's a kind of assimilation.

[s] after a voiceless consonant (except sibilants), as in tops, pots, docks, breaths, laughs

[əz] after a sibilant, as in chuches, judɡes, rushes, faces, crazes

[z] everywhere else, as in pods, luɡs, fobs, breathes, loves, ɡoes, does, airs, dwells, man's, mom's, sings

This message has been edited. Last edited by: goofy,

Thanks, goofy. It was late when I posted that. Also, I have noticed some pronounce the -es after sibilants more like /ɪz/ than /əz/.