How to Pronounce -S and -ES Endings: /s/, /z/ or /ɪz/

The letter s at the end of an English word does three grammatical jobs: it makes nouns plural (cats), marks the third person of verbs (she works), and shows possession (John's). It also stands for is and has in contractions (it's, he's gone). All of these follow one pronunciation rule.

The rule has three outcomes: /s/, /z/ or /ɪz/. Most learners know it in theory, but in practice two errors are very common: pronouncing every ending as /s/, and dropping the ending in consonant clusters. The first sounds accented; the second changes the grammar.

The rule

This is the same logic as the -ed ending. After a sound that is too similar to /s/ or /z/, English inserts a vowel so the ending can be heard. Otherwise the ending agrees in voicing with the sound before it.

As with -ed, what counts is the final sound. Pages ends in the letter e but the sound /dʒ/, so it is /ˈpeɪdʒɪz/. Laughs ends in /f/, so it takes /s/. Boxes ends in /ks/, so it takes /ɪz/.

Why the /z/ ending matters

Many languages, including Spanish, Portuguese, Italian, German, Russian and Turkish, either have no /z/ at the end of a word or turn it into /s/. Speakers of those languages tend to use /s/ for every ending: dogs becomes /dɒɡs/.

That rarely causes a misunderstanding on its own, but it interacts with something English listeners depend on: vowels are longer before voiced consonants. Compare these pairs, which differ only in the final /s/ or /z/:

Say each pair and notice that the vowel in the right-hand column is audibly longer. In fact, native speakers often devoice a final /z/ themselves, especially before a pause, and listeners still hear eyes rather than ice because of the vowel length. So if you find /z/ hard to voice at the end of a word, the practical fix is to lengthen the vowel before it. That carries most of the information.

The ending inside consonant clusters

The second common error is dropping the ending when it creates a cluster: she work for she works, two month for two months. This happens most with speakers of Chinese languages, Vietnamese, Thai and Japanese, whose languages allow few or no consonants at the end of a syllable.

Here the ending carries grammar, so losing it matters more than mispronouncing it. The hardest cases are the ones where the plural or verb ending creates three or four consonants:

• texts /teksts/, tests /tests/, costs /kɒsts/, desks /desks/
• months /mʌnθs/, lengths /leŋθs/, sixths /sɪksθs/
• asks /ɑːsks/ (American /æsks/), helps /helps/, films /fɪlmz/

Native speakers simplify some of these in casual speech. Months is often [mʌns] and tests can become [tess]. But notice what they keep: the final /s/, which carries the grammar. If you have to lose something, lose a consonant in the middle, never the ending.

Nouns that change their final sound

A small group of nouns change their last consonant from voiceless to voiced before the plural ending. The spelling shows it in some words and hides it in others.

Houses is the one to learn first, because it is very common and nothing in the spelling warns you. Saying /ˈhaʊsɪz/ is understood, but it is one of the most frequent small errors in otherwise fluent learner speech. Clothes, which looks like a plural of cloth but is not, is usually pronounced /kləʊz/ in natural speech, rhyming with goes.

Contractions and possessives

The same rule applies when 's stands for is, has or possession:

• it's /ɪts/, what's /wɒts/, Pat's /pæts/: /s/ after a voiceless sound
• he's /hiːz/, John's /dʒɒnz/, the car's: /z/ after a voiced sound
• George's /ˈdʒɔːdʒɪz/, the boss's /ˈbɒsɪz/, Liz's /ˈlɪzɪz/: /ɪz/ after a hissing or hushing sound

With names ending in /s/ or /z/, spelling varies (James's or James'), but most speakers pronounce the extra syllable either way: /ˈdʒeɪmzɪz/.

Practice sentences

Read these aloud, recording yourself. For each underlined ending, decide in advance whether it is /s/, /z/ or /ɪz/, then check the recording.

1. She watches the news and reads the papers every morning.
2. The boxes in the houses have books, clothes and dishes.
3. He asks questions, takes notes and tests every idea.
4. It costs six months' salary.

Answers: watches /ɪz/, news /z/, reads /z/, papers /z/; boxes /ɪz/, houses /ɪz/, books /s/, clothes /z/, dishes /ɪz/; asks /s/, takes /s/, tests /s/; costs /s/, months /s/.

Frequently asked questions

Is it wrong to pronounce every -s ending as /s/?

It is understood in most cases, but it sounds accented and can blur pairs like rice and rise. If a final /z/ is hard for you, make the vowel before it longer: listeners rely on vowel length as much as on voicing.

How is houses pronounced?

As /ˈhaʊzɪz/, with /z/ in the middle. The singular house has /s/, but it changes to /z/ before the plural ending. The spelling does not show this.

Do native speakers simplify words like months and texts?

Often, in casual speech: months can sound like [mʌns] and texts like [teks]. But they almost always keep the final /s/, because it carries the grammar. Learners should do the same.

Sources and further reading

• Roach, P. (2009). English Phonetics and Phonology (4th ed.). Cambridge University Press.
• Swan, M. (2016). Practical English Usage (4th ed.). Oxford University Press.
• Wells, J. C. (2008). Longman Pronunciation Dictionary (3rd ed.). Pearson Longman.

Read More in This Topic

• How to Pronounce -ED Endings: When It Is /t/, /d/ or /ɪd/
• Consonant Clusters and Syllable Structure in English
• Voiced vs Voiceless Consonants in English: The Acoustic Difference That Matters

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