Learning how to pronounce the S and Z sounds in English is one of those tasks that looks trivial on paper and turns out to matter more than you expect. These two sounds share almost identical mouth positions — same teeth, same tongue placement — and yet they are distinct in ways that affect meaning, and in ways that listeners notice even when they cannot name what sounds slightly off. If you have ever been told your English sounds "a bit flat" or "a bit harsh", this pair of sounds may be part of the reason.
By the end of this article, you will be able to feel the physical difference between S and Z, apply the correct sound to plurals and verb endings, and stop second-guessing words like because, easy, and his — which are far more commonly mispronounced than most learners realise.
The Core Distinction: Voiced and Voiceless
English consonants often come in pairs: two sounds made in exactly the same place in the mouth, with exactly the same airflow, differing only in one thing — whether the vocal cords are vibrating. These are called voiced and voiceless pairs.
S is voiceless. Z is voiced. That is the whole story, mechanically.
To feel this directly, place two fingers lightly against your throat and say a long, sustained "sssss". You should feel almost nothing — perhaps a faint hiss of air, but no vibration. Now switch to "zzzzz". The buzzing you feel under your fingertips is your vocal cords at work. The Z sound is essentially S with your voice switched on.
This voiced/voiceless distinction runs through English. The same relationship exists between F and V, between P and B, between T and D. Once you train yourself to hear and feel it in one pair, the others become easier.
Where Each Sound Actually Lives in Words
This is where many learners are caught out: the spelling of a word is a poor guide to whether you should use S or Z.
The letter S can represent a Z sound
Consider these common words:
- his — the S is pronounced /z/
- these — the S is pronounced /z/
- rose — the S is pronounced /z/
- easy — the S is pronounced /z/
- because — the S is pronounced /z/
- present (verb) — the second S is pronounced /z/
None of these have the letter Z in them. All of them end on, or contain, a voiced sound. This is the pattern: when the letter S falls between two vowels, or follows a voiced sound at the end of a word, it usually takes a Z sound. English spelling simply never got around to reflecting this.
The letter Z is almost always /z/
The letter Z, at least, is consistent. Zero, zone, amazing, frozen, prize — these all carry the voiced sound. The only notable exception is the word pizza, where the double Z represents a /ts/ sound borrowed from Italian.
The Plural Rule: Three Endings, Not One
One of the most practical applications of this distinction is the English plural. Many learners say every plural S as a voiceless /s/, and it creates a slightly mechanical, over-clipped quality to their speech. In reality, the plural ending has three forms.
After voiceless consonants — use /s/: cups, cats, books, roofs, months
After voiced consonants and vowel sounds — use /z/: dogs, cars, birds, days, trees, ideas
After sibilant sounds (s, z, sh, ch, j) — use /ɪz/, an extra syllable: buses, roses, watches, bridges, mazes
The same three-way rule applies to the third-person singular verb ending (he runs, she watches, it buzzes) and to possessive S (the dog's lead, the boss's car).
Work through these out loud:
"The cats sat on the dogs."
Cats ends with the voiceless /s/; dogs ends with the voiced /z/. Both use the letter S in the plural, but they sound different. If you say both the same way, the sentence is still understandable — but it marks you as someone who has not yet internalised how English rhythm works.
Minimal Pairs: Words Where the Difference Changes Meaning
In most everyday speech, swapping S for Z will not cause a breakdown in communication — context rescues you. But there are genuine minimal pairs where the sounds are the only thing separating two different words:
| S sound | Z sound |
|---|---|
| sip | zip |
| seal | zeal |
| sink | zinc |
| bus | buzz |
| race | raise |
| price | prize |
| close (adjective) | close (verb) |
That last pair is worth dwelling on. The door is close (nearby) uses a final /s/. Please close the door (shut it) uses a final /z/. Same spelling, same word, different sound, different meaning. English has quite a few of these — house as a noun takes /s/, to house as a verb takes /z*/.
Exercises to Build the Habit
Step one: Find the buzz
Hum normally. That vibration is voiced sound. Now, without stopping the hum, bring your teeth close together and let the hum narrow into a "zzzzz". Hold it for five seconds. Repeat. You are training your vocal cords to stay engaged for a consonant — something that feels unnatural if your first language has no voiced sibilant.
Step two: Contrast pairs slowly
Pick a minimal pair — say, sip and zip — and say them alternately, slowly, with a pause between. Do not rush to fluency. The goal at this stage is to feel the switch: voice off, voice on. Once you can feel it, you can build speed.
Step three: Read plurals aloud with intention
Take any paragraph of written English — a news article, a page of a novel — and read it aloud, paying specific attention to every plural and verb ending. Before you say each one, decide: voiceless /s/, voiced /z/, or extra syllable /ɪz/? This is slow work at first, but it builds the habit of noticing, which eventually becomes automatic.
Step four: Record and listen back
The ear you use for your own voice while speaking is unreliable — you hear yourself partly through bone conduction, which distorts what you actually produce. Recording yourself and listening back closes that gap. Say a sentence like:
"He loves jazz and his sister plays in a band in Leeds."
Count how many voiced Z sounds appear. (loves, jazz, his, sister, plays, Leeds — six.) Listen back. Are they all voiced? Or are some of them clipped into a voiceless /s/?
Tools like ummute give you feedback on exactly this kind of detail, flagging where your voicing is inconsistent so you are not guessing in the dark.
A Note on Accent and Intelligibility
Perfecting S and Z is not about sounding like a native speaker of any particular variety of English. It is about being clearly understood. Voicing is a feature of nearly all world Englishes — British, American, Australian, Indian, Nigerian — so getting it right improves your intelligibility across accents, not just in one regional context. That matters whether you are in a meeting, on a call, or giving a presentation. You can read more about what makes speech genuinely clear on our benefits page.
The S and Z sounds are a small thing, but spoken language is built from small things. Reliable voicing on plurals, verb endings, and everyday words like because and his is one of those adjustments that quietly upgrades how natural your English sounds — not by changing your accent, but by making your speech more consistent with the patterns English listeners expect to hear.