I remember walking near the coast with a Spanish friend of mine a couple years ago. She was showing me around a village. At some point, we walked by some kind of building and I wondered what it was. She told me that it was a place where people would sell poison... I scratched the back of my head and looked at her in a puzzled way. I was confused. And then I finally got it after a few seconds. It took me a moment to realize that she actually meant fish instead of poison.

Why am I telling you this story? Because it all happened in French, and that is when I started to notice that Spanish speaking people tend to struggle with the /s/ and /z/ sounds because the latter doesn’t exist in their language. Indeed, these two words are respectively pronounced /pwasɔ̃/ and /pwazɔ̃/ in French. If you got that, that’s perfect, but for some people, it might be very subtle (some people hardly hear a difference).

That is why in today’s article, I am going to tell you in which cases the letter s sounds like /s/ (as in the word “serpent”), and when it sounds like /z/ (as in “zebra”). You should also note that the first sound can also be related to different orthographies.


There are several cases when the letter s should sound like an /s/:

When a word begins with an s (ex: serpent, souvent, sinon)
When there is a double ss within or at the end of a word (ex: passer, casser, stress )
Before or after a consonant (ex: moustique, lustre, adversaire)
In some words ending with an s (ex: os, ours, as)

Attention! Sometimes the finale s can be silent. For example, in the words dos (/do/) and pas (/pa/), the final letter is muted. That is also the case for the plural (unlike in Spanish for instance where the finale s would be pronounced). French, why are you so complicated?

Sometimes the sound /s/ can have a different orthography than the letter s:

When words contain ç (ex: garçon, déçu, ça)
When words contain a c placed in front of an e, i or y (ex: morceau, musicien, encyclopédie)
When words contain the group of letters sc from Latin (ex: science, obsolescence, fasciner)
When words either contain the group of letters tia, tie or tion (ex: spartiate, diplomatie, addition)
In some words in which there is a z before or after a consonant (ex: tzigane, quartz, aztèque)
In some numbers with the letter x (ex: six, dix, soixante)


Now, when should you make the /z/ sound?

When the letter s is situated between two vowels (ex: maison, raser, musique)

Attention! This is not the case when the word contains a prefix (ex: présupposé, parasol, vraisemblable).
- When there is a z (ex: bizarre, zeste, treize)
- When a word ends with an s and the following one begins by a vowel, this is called a liaison. (ex: les_autres, pas_encore, les_ustensiles)

Attention! When there is a double zz, it is pronounced [dz] (ex: pizza)

Also, sometimes a single sound can completely change the meaning of what you are trying to say!

Here is a list of examples:

Embrasser - /ɑ̃bʀase/ (to kiss) =/= Embraser - /ɑ̃bʀaze/ (to set alight)
Hausse - /ˈos/ (increase) =/= Ose - /oz/ (dare)
Dessert - /desɛʀ/ (dessert) =/= Désert - /dezɛʀ/ (desert)
Russe - /rys/ (Russian) =/= Ruse - /ryz/ (a trick)
Coussin - /kusɛ̃/ (cushion) =/= Cousin - /kuzɛ̃/ (cousin)
Basse - /bas/ (a bass guitar/low) =/= Base - /baz/ (base)
Frisson - /fʀisɔ̃/ (shivers) =/= Nous frisons - /fʀizɔ̃/ (we skim)
Rosse - /ʀɔs/ (nasty) =/= Rose - /ʀoz/ (rose)
Casse - /kɑs/ (damage, robbery) =/= Case - /kɑz/ (compartment, square)
Tresse - /tʀɛs/ (braid) =/= Treize - /tʀɛz/ (thirteen)
Face - /fas/ (face, side) =/= Phase - /faz/ (phase)
Crisser - /kʀise/ (squeak) =/= Criser - /kʀize/ (to throw a tantrum)

To master that subtle difference, I think you should first train your ears to actually hear it by speaking to a native. There are also great resources available online. Have a look at the website forvo.com, which should help you with pronunciation.

Once your ears are familiar with these two sounds, you should then train your tongue to build muscle memory. Don’t rush it! Take a word and first read it in your mind, figure out whether it has an /s/ or a /z/ sound, and then say it out loud. Pronounce it slowly, making sure it will stick in your mind more easily. If you can’t articulate a word correctly slowly, you won’t be able to enunciate it at a conversation speed. Then ask somebody to correct you or check the “answer” online. If you are wrong, well, it should help you remember. See it as a game.

Granted, all that can be very confusing! But don’t you worry too much about it because you will be understood anyway if you make a mistake and change a [z] for an [s]. But next time you want to order fish at a restaurant, think twice or it could turn into a very funny situation!

Good luck and remember to have fun while learning!

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