s / z

This is one of the most difficult pairs of consonant sounds for Spanish speakers. As in previous cases, /s/ and /z/ are the same sound except for the voicing. The problem is that the voiced phoneme /z/ doesn’t exist in Spanish, where this type of sound is always voiceless. And the whole thing is further complicated by the intricate spelling and the devoicing of final consonants. For many Spanish speakers it takes some time and effort to distinguish between /s/ and /z/ and start producing them as separate sounds. However, the good news is that the cases where this confusion can lead to misunderstanding are not too many and fairly well-known.

Let’s start by listening to some minimal pairs in which the difference between /s/ and /z/ is pretty obvious.

sound_loud_speaker muscle – muzzle

sound_loud_speaker sewn – zone

sound_loud_speaker fussy – fuzzy

sound_loud_speaker device – devise

sound_loud_speaker loose – lose

And here is a recording by a native speaker where the difference between the two phonemes can be appreciated:

sound_loud_speaker For me a script is a bit like the clues of a crossword (Jeremy Irons, BBC4). /skrɪpt/ /kluːz/ /ˈkrɒswɜːd/

s (alveolar, fricative, voiceless)

Spelling: s (send), ss (mess), c (cigar), ce (niece), sc (ascend).  x, xe and xc are often pronounced as /ks/ (tax,  axe, excellent)


The phoneme /s/ doesn’t present any problems to Spanish speakers because it’s the same used in Spanish. In fact, the real problem is that Spanish speakers tend to do every sound of this type as /s/.

Here are some examples of the phoneme /s/ by native speakers:

sound_loud_speaker This definition of the obsessive rumination on what appears to be a single piece of damming evidence (Kenneth Branagh, BBC4).

sound_loud_speaker A star of silent cinema, the talkies have made her redundant and she lives as an eccentric recluse in her Hollywood mansion (John Wilson, BBC4).


z (alveolar, fricative, voiced)

Spelling: z (zoo), ze (gaze), zz (dizzy), s (always, season), se (nose). x is often pronounced /gz/ as an alternative to /ks/ (exact). Exceptional spelling: ss (scissors, dessert), x at the beginning of words (xenophobia).


Here the matter is altogether more complicated. Let’s try to break down the problem into different parts. A Spanish learner of English normally has to address three tasks:

  1. To learn how to produce the /z/ sound.
  2. To recognize it when he or she hears it.
  3. To know in which words has to be used.


1. Producing the /z/. 

As you know /z/ is the voiced counterpart of /s/, so we’ll follow the usual procedure. You have to produce a long /s/ and then add the voicing. Like this:

From /s/ to /z/ sound_loud_speaker

Listen to the two different sounds and try to produce them yourself:

sound_loud_speaker Seal   /siːl/                           sound_loud_speaker Zeal  /ziːl/


2. Recognizing the /z/. 

In the following recordings, the voiced nature of /z/ is very clear. Listen to the letters marked in red and you’ll hear that those sounds are produced with vocal fold vibration. This process of identifying a sound takes some students more time than others. So, if you don’t recognize the /z/ immediately, keep trying. I can assure you that, in the end, everybody manages to tell the difference.


sound_loud_speaker But if calm reason has not worked, I should give them noisy reason (Julian Barnes, BBC4).

sound_loud_speaker If she refuses he demands the death penalty (Trevor Nunn, BBC4).

sound_loud_speaker So, you don’t lose people, I wanted to say that (Judith Kerr, BBC4).

sound_loud_speaker One knows that although you’re always very sorry to lose what is being cut (Jeremy Irons, BBC4).


3. Where does the sound /z/ go? 

This is one of the worst conundrums of English pronunciation. But don’t panic. Even though there are many words you’ll just have to learn by heart, there are also some very useful guidelines that’ll make your life easier. Let’s summarize the most important facts.

  • The letter z  is always pronounced as /z/. So zoo is pronounced /zuː/, which makes it different from the name Sue /suː/.

Listen to the way zoomed up  is pronounced at the end of this example:

sound_loud_speaker And as soon as I saw that the first fellowship was given to Alfred Hitchcock, who directed my father in his first film, I just zoomed up to the top of the clouds (Vanessa Redgrave, BBC4).

  • When the letter z is doubled, the pronunciation is exactly the same. So, dizzy is said /dɪzi/ sound_loud_speaker, not /dɪtzi/ or /dɪdzi/.
  • The letter c is never pronounced as /z/. So face is always /feɪs/ sound_loud_speaker, which makes it different from phase /feɪz/ sound_loud_speaker.

The real trouble comes with the letter s, which can be pronounced in both ways. Again, I’ll try to give you some clues.

  • S is never pronounced as /z/ at the beginning of words (just in middle and final position). So, Sue will always be /suː/. You can see it clearly in this example:

sound_loud_speaker And as soon as I saw that the first fellowship was given to Alfred Hitchcock (Vanessa Redgrave, BBC4).

  • One of the most important cases, the s added in plurals and in the third person of verbs in simple present, follows a very precise rule. The phoneme depends on the voicing of the previous consonant. If that last sound is voiceless, the s will be pronounced as /s/ (cats /kæts/, thinks /θɪŋks/). If it’s voiced, the s will be /z/ (dogs /dɒgz/, bends /bendz/).
  • Some words which can function as both nouns and verbs are usually pronounced with /s/ in the noun and /z/ in the verb. Like in these examples:

sound_loud_speaker The House of Commons /haʊs/ (noun).             sound_loud_speaker We were housing a bunch of dogs and cats /haʊzɪŋ/ (verb).

  • On many occasions, there are no rules and the pronunciation has to be looked up. This is particularly true when the s comes in mid-position, and it’s an important case because in mid-position the voicing is sometimes very noticeable, especially between vowels. Look at how clearly the two sounds can be distinguished in the following example. Pay special attention to the word disaster /dɪˈzɑːstə/.

sound_loud_speaker What Titania describes is a kind of ecological disaster that has overtaken the world, and this disaster is because they are in dispute over the ownership of an Indian boy (Trevor Nunn, BBC4).


Now, have a look at this example:

sound_loud_speaker A seal’s flippers resemble our hands (A.S. Byatt, on BBC4).

The /z/ is very clear in resemble, isn’t it? But what about the other letters ? Let’s proceed step by step. The first s in seal’s is clearly an /s/ because it’s at the beginning of the word. But what happens to the second s (seal’s), and also to those in flippers and hands? They should be voiced, but actually they don’t sound voiced. Why is it? The answer is in the next point.


Devoiced s in final position. As we said before, voiced consonants are usually devoiced in final position unless they are followed in speech by a voiced sound, so many times the difference between /s/ and /z/ is neutralized. Have a look at this example:

sound_loud_speaker This definition of the obsessive rumination on what appears to be a single piece of damming evidence (Kenneth Branagh, BBC4).

The s in appears should be pronounced as /z/, but since it’s placed in final position and followed by a voiceless sound is clearly devoiced (it sounds as /s/). So the letter s at the end of words is a bit of a quagmire. It depends on many factors, but they tend to be devoiced unless they are clearly linked to a voiced sound in speech.

Look at this example:

sound_loud_speaker He play(devoiced, almost as /s/).     sound_loud_speaker He plays to kill time (devoiced, almost as /s/).       sound_loud_speaker He plays alone (followed by a voiced sound and then said as /z/).

In conclusion, you shouldn’t worry too much about it, unless the linking to a voiced sound (especially if it’s a vowel) is perfectly clear, in which case it’s better to make an effort and pronounce it as /z/.


This is the type of work I do with my students in my one-to-one classes. I make them practise these processes with exercises until they improve their comprehension of native speakers and are capable of speaking like that themselves. If you are interested in my classes, you can contact me here.


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