"s" and "z"

Question

I have a question about the difference between "s" and "z". Hope you can help me.

"s" is voiceless and "z" is voiced. However, I find it very difficult to distinguish them when they are at the end. In many cases, even when I play the sound files again and again, I still can't tell the difference between an "s" and a "z". Is it because of my ears or is there really not much difference? Or native speakers actually sense the difference from the length (and the subtle tone change) of the preceding vowel?

I also found some websites saying that the "z" is often partially and completely devoiced. I really can't make sense of this. What is the difference between a devoiced "z" and an "s"?

Zerox · Accepted Answer

Normally when /z/ is intervocalic, that is, between two vowels, it is fully voiced, otherwise partly or fully devoiced. Say, for example, 'vases' and you can feel the vocal cord vibration with the first /z/. The second /z/ in the word is devoiced but it still has friction noise. There are mainly two things how to separate between an unvoiced fortis sibilant /s/ and devoiced lenis sibilant /Z/ ( Notice, here I use a capital 'z' to indicate that it is devoiced). First, /s/ is louder than /Z/, it requires greater breath force and muscular effort. Second, the vowel preceding fortis is a bit shorter than before a lenis sound.

Hopefully this helped you in some way.

Pter · Answer

Thanks Zerox. Just want to check if I understood it correctly.

Are they devoiced /z/?

1. absorbs, clouds, bags, levels, dims, unions, cheers, evolves

However, if the final "s" follow a vowel, I found from the dictionary that sometimes it is /z/ and sometimes it is /s/.

These are indicated as /z/ in the dictionary:

2. grandpas, has (strong form), says, pies, fixes, togas, Achilles, hers

But these are indicated as /s/ in the dictionary

3. class, gas, assess, analysis, happiness

I really can't figure out a rule when is an "s" /z/ and when is it /s/ when following a vowel.

I am completely amazed by the following pairs:

close adj. /s/
close v /z/

abuse n /s/
abuse v /z/

diffuse adj /s/
diffuse v /z/

excuse n /s/
excuse v /z/

How important is the difference in the pronunciation of all these ending voiced /z/, devoice /z/ and /s/. Can people really notice the difference? Pronouncing /z/ is quite natural to me when it is between two vowels, but I find it very difficult to pronounce a voiced /z/ at word finals. It I pronounce all of them as /s/, would you find it strange?

CalifJim · Answer

Is it because of my ears or is there really not much difference?

Your ears.

How important is the difference in the pronunciation of all these ending voiced /z/, devoice /z/ and /s/.

It's very important. Well, the difference between /s/ and /z/, anyway. Maybe the devoiced /z/ is not so important. Practice with /z/ and imitate native speakers, and you'll automatically produce the correct forms.

Can people really notice the difference?

Yes. Native speakers have no trouble hearing the difference between the verb and noun pronunciations of use, for example.

I[ f ] I pronounce all of them as /s/, would you find it strange?

Yes. That would be strange.

Maybe you just need to practice a little more. Eventually you'll get it.

CJ

Pter · Answer

Thank you very much CJ.  However, I still can't quite figure out how to pronounce the devoiced /z/.  Is it more like /s/ or the voiced /z/?

Zerox · Answer

I haven't come across with a clear rule that states when to use fortis or lenis sound after a vowel, perhaps CJ has more information on this matter.

However, there is a simple rule for the following suffixal consonant, that is , for those 's'-markers such as clouds. Simply put, the rule is fortis+fortis and lenis+lenis. So, the word 'cloud' ends in a lenis sound, hence a lenis sound follows, that is, /z/. Moreover, although /nml/ don't have the normal fortis/lenis pairs, they are considered voiced sounds. Therefore, they are followed by a voiced lenis sound, as in levels. However, notice the exception with sibilants. With these the ending is /iz/, for example 'buses, kisses, bushes'.

Perhaps you can hear the difference between /s/ and /z/ if you say them yourself. Try saying cats(ends in a fortis /t/) and dogs(ends in a lenis /g/) one after the other. Notice also that final /z/ in 'dogs, robs, kills' is extemely weak and barely audible.
If you have trouble making the distinction, make only the sibilant sounds /s/ and /z/. Be sure that your tongue is in the right place. Then start making /s/ and move to /z/. Your tongue doesn't move at all when you make the shift, only your vocal cords start to vibrate with the /z/.

Hopefully this was of any help.

Carson21 · Answer

I don't know what you guys are all on about with devoiced /z/. It's not a devoiced /z/, it's just /s/. In the example that someone above used, "vases"... I don't know about up North or across the pond (either one), but American Standard has that as /s/ in the medial and /z/ in the final. Well, if you pronounce the <a> like you do in "bratwurst" or "father", then the medial would become /z/.

Pter, the basic rule is this: final <s> becomes voiced to /z/ when it is final in most verbs and/or after a voiced stop (/g b d/ etc). It remains unvoiced /s/ for most nouns and adjectives. It also can voice when the closest (previous) consonant was already /s/. (Abuses, vases, faces, places)

Here's the other basic rule that will probably help you, even if at first it seems to be "maddening the unhelpful": In English, there are a million rules, and every rule has a million exceptions. English is probably as far removed from a loglang as you can get, so it helps to just accept what you learn at face value and imitate it, rather than trying to figure out "why". You can ask "why" all day and use up all the time where you could have been moving on to the next rule. Look at the general rule for each case, then apply it. You learn irregularities as you go (much like learning Spanish verbs).

The perfect example of an exception: assess. It has /s/ in the medial AND final. D'oh! Just have to remember that one.

As for how important it is that you learn the difference between /s/ and /z/... I don't think it's that big a deal. If the spelling shows <s>, then saying /s/ or /z/ won't make much of a difference if your goal is to just be understood. They're allophones, essentially. We could drop <z> from our orthography and get along just fine. However, if your goal is to sound like a native speaker, then, yes, it's quite important that you can make the distinction.

Last, if you pronounced all <s> as /s/... You might sound strange to most people in the UK and the northern United States (plus the commonwealth), but anywhere in the West, Southwest, South East, and Border states in the US, no one would think twice about it! There are a lot of people in those regions that speak English as a second language with Spanish as their first, and they tend to always use /s/ for <s> , regardless of typical conventions.

Zerox · Answer

Yes, I should have checked with which pronunciaion you speak. My examples concern mainly BrE.

Anonymous · Answer

Without going into the technical stuff here's my tip for making an S or a Z.

S - imagine your bicycle tire has got a small hole in it. What is the sound of the air leaking out. A hissssssssss....

Z - a wasp/bee is getting angy around you. What noise is it making? Buzzzzzzzzzzzzzzzzzz..........

Pter · Answer

Thank you very much CJ, Zerox, and Carson. You all have given me very valuable advices. After reading through all you said carefully, and then watching a couple of English TV programmes, I believe I can now tell the difference! The ending /z/ in most cases are much shorter, voiced but less audible than the hissing sound of the ending /s/. Now, I found out what's the problem. Those sound files I was listening to are from a pronouncing dictionary. And perhaps in trying to make them as clearly audible as possible, both the ending /s/ and ending /z/ are spoken very "clearly" and become unnatural.

For people like me that learn English as a second language, we are often influenced heavily by our mother tongue. This is like looking at something through a piece of tainted glass. In those aspects where our mother tongue has big differences with English, unless we are told the rules explicitly, we often never realize how people really say them in English just by listening. My mother tongue does not have any voiced consonants and consonant clusters, therefore, it is quite a challenge for me to learn how to pronounce a cluster of voiced consonants, such as /-ndz/, /-gz/, /zd/.

Again, thank you very much to you all. You really helped me a lot!

===
EDIT:

Let me summarize what I have learnt here plus a little that I have discovered myself.

1. Final voiced consonant (b, d, g, l, m, n, ng, r, v, voiced th) + s ---> /z/
2. Final voiceless consonant (f, k, p, t, voiceless th) + s ---> /s/
3. Final vowel + s ---> no rules, except when any of the following rules apply
4. Some words that can be used both as verb and noun/adjective ---> verb: /z/, noun or adjective: /s/
5. Words ending in -as, -is, -os, -us:
when the s is part of the word in its basic form (not plural or third party singular verb) ---> /s/
when the s is added to make it a plural or third party singluar verb ---> /z/
6. Words ending in -ces, -des, -oes, -shes, -ses, -zes ---> /z/
7. Words ending in -sis, -nce, -nse, -ss (including -less, ness), -sce ---> /s/
8. /z/ is more common than /s/ overall

Zerox · Answer

You pointed out an important issue. Usually when a native is speaking to a foreigner, they slow down their speech and pronounce words more carefully than they would in their normal speech. Although, this is extremely kind of them, they actually do us, foreigners, a disservice by speaking with strong forms. And if foreigners hear too much of this 'foreign English', they have hard times listening normal conversations in normal speed.

"s" and "z"

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