So, I've seen this rule at several English books about how if a word has a voiced final sound (e.g. r, voiced th, l, m, n..) then added 's' is pronounced more like /z/. If the final sound is voiceless (e.g. t, p, k etc) then it's pronounced like /s/.


But, in practice, I see this rule violated often for several instances, at least in GenAmE (standard/General American Accent). Examples:

  • Some words ending with L/N sounds: Falls, malls, aliens, holes (sounds like final s is still /s/ not /z/ in falls, malls, aliens, wells, holes)

  • Doesn’t seem to happen in some words ending with ‘m’: E.g. dreams, problems, times

  • Doesn't happen for some words ending in ‘r’: E.g. truckers/f**ers seems to be pronounced with /s/ at the end rather than /z/

I can see some people still using slight /z/ sound (not full blown /z/ but somewhere in the middle of /s/ and /z/) but I think many standard US english speakers still would be pronouncing them with more of /s/ than /z/ sound in the final position for these words. It also seems like people aim for /s/ sound but since the final sound in the word was voiced, a slight /z/ (not full-blown) may sneak in, which may give the impression of a slight /z/ mixed with /s/. Still, in these cases, the "Rule" doesn't apply and is more of an aberration than the standard practice.


  • Why is this then stated as a 'rule' when clearly it's not so cut-and-dried?

  • Can someone explain the basis for this so-called 'rule' when there are so many instances of standard american speech pattern deviating from it?

marked as duplicate by sumelic pronunciation Apr 21 at 2:38

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  • General American is rather broad - can you indicate what region(s) you have heard this in? – Mark Beadles Apr 20 at 23:34
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    I see what you mean. The z is voiced, but in the examples you give, the speakers cut them so short that it is hard to hear it, To a native speaker, false and falls never sound the same except occasionaly in the upper Midwest. It never sounds incorrect to fully voice the Z sound, but not to voice it will sound strange to most people. In your examples it is voiced, but truncated. One does not have to truncate it to sounds normal. – user344654 Apr 21 at 0:06
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    Btw, You are correct that it should not be called a rule. The English language does not have rules, only conventions. – user344654 Apr 21 at 0:09
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    @JoeBlack I think you're simply hearing it wrong. And you shouldn't believe artificially generated examples, either. Your youtube examples are horrible. The voicing "rules" are not things that people are taught, but rather unvarying phonologic laws of assimilation that simply fall out of the language’s phonotactics. If you don’t do it, people will understand you in most cases, but it will sound foreign and unnatural. – tchrist Apr 21 at 0:11
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    Americans generally do not confuse falls and false. We tell them apart both by the voicing of the final consonant and by the fact that falls has a longer vowel than false (because the final consonant is voiced). So we hear the phoneme /z/, even when some foreigners might hear /s/. – Peter Shor Apr 21 at 1:16