Good news: you do not need to learn a new rule for possessive 's. The apostrophe-s that shows ownership follows the exact same 3-sound pattern as plural -s and third-person verb -s. If you have studied those rules, you already have everything you need.
If you want a full breakdown of all the phonetic details behind the rule, check out our guide: The 3 Sounds of -S Endings: Complete Pronunciation Guide. This post focuses specifically on how those same sounds work with possessives.
Quick Rule Recap
The sound of possessive 's depends on the final sound of the noun it attaches to (not the final letter, the final sound).
| Final Sound of the Noun | Possessive Pronunciation | Examples |
|---|---|---|
| Voiceless: /p/, /t/, /k/, /f/, /θ/ | /s/ | Kate's, Jeff's |
| Voiced consonants + all vowels | /z/ | John's, Anna's |
| Sibilants: /s/, /z/, /ʃ/, /ʒ/, /tʃ/, /dʒ/ | /ɪz/ (extra syllable) | James's, Grace's |
Possessive 's with Names
Names are the most common place you will use possessive 's in everyday English. Apply the rule to the final sound of the name.
Both Kate (/keɪt/) and Jeff (/dʒɛf/) end in voiceless sounds (/t/ and /f/), so possessive 's is pronounced /s/.
John (/dʒɑn/) ends in /n/, a voiced consonant. Anna (/ˈænə/) ends in a vowel sound. Both take /z/.
Mark (/mɑrk/) ends in /k/, a voiceless sound, so it takes /s/. David (/ˈdeɪvɪd/) ends in /d/, a voiced consonant, so it takes /z/.
Possessive 's with Common Nouns
The same rule applies to everyday nouns. Focus on what sound the noun ends in, not what letter it ends in.
Notice that boss (/bɔs/) and church (/tʃɝtʃ/) both end in sibilant sounds, so they take the extra syllable /ɪz/. Dog (/dɔɡ/) ends in /ɡ/ (voiced), so it takes /z/. Cat (/kæt/) ends in /t/ (voiceless), so it takes /s/.
Tricky Cases
| Case | Example | Pronunciation | Note |
|---|---|---|---|
| Names ending in /s/ or /z/ | James's, Chris's, Liz's | /dʒeɪmzɪz/, /krɪsɪz/, /lɪzɪz/ | Always add /ɪz/ (extra syllable) |
| Names ending in /ks/ | Max's, Alex's | /mæksɪz/, /ˈælɪksɪz/ | /ks/ ends on the sibilant cluster, so /ɪz/ |
| Irregular plurals | children's, women's, people's | /ˈtʃɪldrənz/, /ˈwɪmɪnz/, /ˈpiːpəlz/ | Treat as singular noun (voiced endings take /z/) |
| Regular plurals (group possession) | the cats', the teachers' | /ðə kæts/, /ðə ˈtiːtʃərz/ | Apostrophe only, no extra sound added |
The irregular plurals (children's, women's, people's) are particularly important. Because these plural forms do not end in -s, you add 's normally and apply the standard 3-sound rule. Children ends in /n/ (voiced), women ends in /n/ (voiced), and people ends in /l/ (voiced), so all three take /z/.
Regular plural possessives (the cats' toys, the teachers' lounge) already have the -s sound from the plural. No additional sound is added; only the apostrophe changes in writing.
Practice Sentences
Read these sentences aloud, paying attention to the bolded possessives.
- Kate's /s/ keys are on the table next to Mark's /s/ wallet.
- John's /z/ dog followed Anna's /z/ cat across the yard.
- James's /ɪz/ apartment is right above the boss's /ɪz/ office.
- We met at the teacher's /z/ desk before going to the church's /ɪz/ garden.
- It was the children's /z/ idea, but David's /z/ plan made it possible.
Common Mistakes
Confusing its and it's
This is one of the most common errors in both speaking and writing. Its (without apostrophe) is the possessive form of "it" and follows the standard rule: it ends in /t/ (voiceless), so the possessive is pronounced /ɪts/. It's (with apostrophe) is a contraction of "it is" or "it has" and is also pronounced /ɪts/. They sound identical, so context determines meaning. Example: "The dog wagged its tail" (possessive) vs. "It's a great day" (contraction).
Forgetting the extra syllable with sibilant names
Learners often pronounce James's as /dʒeɪmz/ instead of /dʒeɪmzɪz/. The -s at the end of James already ends in a sibilant /z/, so you must add the full /ɪz/ syllable. The same applies to Grace's (/ɡreɪsɪz/), Chris's (/krɪsɪz/), and Max's (/mæksɪz/). If you skip the extra syllable, your listener may not hear the possessive at all.
Using /s/ after all voiced sounds
Some learners default to /s/ for every possessive because it feels safer or more formal. This produces unnatural results. "John's" pronounced as /dʒɑns/ sounds clipped and foreign to native English ears. Trust the rule: voiced ending means /z/.
Treating regular plural possessives as double -s
"The cats' food" is written with an apostrophe but spoken exactly like "the cats" (/kæts/). There is no extra syllable or sound. The apostrophe is purely a spelling convention to signal group possession.