Most English plurals follow a simple rule: add -s or -es to the end of the word. But some of the most common English words break this rule entirely. Instead of "foots" we say feet. Instead of "childs" we say children. And instead of "mouses" we say mice.
These irregular plurals are not just different in spelling. They often have completely different vowel sounds from their singular forms, which means you need to learn their pronunciation separately. This guide will help you master each one.
Why Do Irregular Plurals Exist?
English inherited these unusual plural forms from Old English and other historical influences. In Old English, different noun classes formed plurals in different ways. While most nouns eventually adopted the simple -s ending, a handful of very common words preserved their ancient forms. Because these words are used so frequently, their old patterns survived.
Understanding the categories of irregular plurals makes them easier to learn and pronounce correctly.
Category 1: Vowel-Change Plurals
The most distinctive group of irregular plurals involves a vowel sound change between singular and plural. The consonants stay the same, but the vowel in the middle shifts. This pattern comes from an Old English process called "i-mutation" or "umlaut."
foot /fʊt/ → feet /fiːt/
The vowel changes from the short /ʊ/ (as in "book") to the long /iː/ (as in "see"). Your lips go from rounded to spread.
goose /ɡuːs/ → geese /ɡiːs/
The vowel changes from /uː/ (as in "food") to /iː/ (as in "see"). Both are long vowels, but the tongue position shifts from back to front.
tooth /tuːθ/ → teeth /tiːθ/
Same pattern as goose/geese. The /uː/ becomes /iː/, while the consonants (including the final /θ/) remain unchanged.
mouse /maʊs/ → mice /maɪs/
Here, the diphthong changes from /aʊ/ (as in "how") to /aɪ/ (as in "my"). Both start with /a/, but the second part of the sound shifts from /ʊ/ to /ɪ/.
man /mæn/ → men /mɛn/
The vowel shifts from /æ/ (as in "cat") to /ɛ/ (as in "bed"). This is a subtle but important change. The mouth opens slightly less for /ɛ/ compared to /æ/.
woman /ˈwʊmən/ → women /ˈwɪmɪn/
This is one of the trickiest words in English! The spelling barely changes (just "a" to "e" in the middle), but the pronunciation changes dramatically. The singular has /ʊ/ in the first syllable, while the plural has /ɪ/. Even more confusingly, the second syllable also shifts from /ən/ to /ɪn/. Many learners pronounce "women" the same as "woman," but native speakers clearly distinguish them.
Category 2: -en Plurals
A small group of English words form their plural by adding -en or -ren instead of -s. This was once a very common pattern in Old English but has mostly disappeared.
child /tʃaɪld/ → children /ˈtʃɪldrən/
This word changes in two ways: it adds the -ren suffix, and the vowel shifts from the diphthong /aɪ/ to the short /ɪ/. The plural also adds an extra syllable, going from one syllable to two.
Category 3: Zero Plurals (No Change)
Some English nouns have the same form for both singular and plural. This is common with certain animals. The pronunciation does not change at all, so context tells you whether the speaker means one or many.
sheep, fish, deer
These words look and sound identical whether you mean one or a hundred. Pay attention to the surrounding words (like "a" vs. "many") to understand the meaning.
Category 4: Foreign-Origin Plurals
English has borrowed many words from Latin and Greek, and some of these keep their original plural forms. These are especially common in academic and scientific language.
cactus /ˈkæktəs/ → cacti /ˈkæktaɪ/
The Latin -us ending changes to -i. The pronunciation of the final syllable shifts from /əs/ to /aɪ/ (like the word "eye"). Note that "cactuses" is also acceptable in informal English.
phenomenon /fɪˈnɑːmɪnɑːn/ → phenomena /fɪˈnɑːmɪnə/
The Greek -on ending changes to -a. The final syllable shifts from /nɑːn/ to /nə/. Be careful not to use "phenomena" as a singular form, which is a common mistake.
Complete Comparison Table: Singular vs. Plural
| Type | Singular | IPA (Singular) | Plural | IPA (Plural) | What Changes |
|---|---|---|---|---|---|
| Vowel change | foot | /fʊt/ | feet | /fiːt/ | /ʊ/ → /iː/ |
| Vowel change | goose | /ɡuːs/ | geese | /ɡiːs/ | /uː/ → /iː/ |
| Vowel change | tooth | /tuːθ/ | teeth | /tiːθ/ | /uː/ → /iː/ |
| Vowel change | mouse | /maʊs/ | mice | /maɪs/ | /aʊ/ → /aɪ/ |
| Vowel change | man | /mæn/ | men | /mɛn/ | /æ/ → /ɛ/ |
| Vowel change | woman | /ˈwʊmən/ | women | /ˈwɪmɪn/ | /ʊ/ → /ɪ/, /ən/ → /ɪn/ |
| -en plural | child | /tʃaɪld/ | children | /ˈtʃɪldrən/ | /aɪ/ → /ɪ/, adds -ren |
| Zero plural | sheep | /ʃiːp/ | sheep | /ʃiːp/ | No change |
| Zero plural | fish | /fɪʃ/ | fish | /fɪʃ/ | No change |
| Zero plural | deer | /dɪr/ | deer | /dɪr/ | No change |
| Latin origin | cactus | /ˈkæktəs/ | cacti | /ˈkæktaɪ/ | /-əs/ → /-aɪ/ |
| Greek origin | phenomenon | /fɪˈnɑːmɪnɑːn/ | phenomena | /fɪˈnɑːmɪnə/ | /-ɑːn/ → /-ə/ |
The Trickiest Pronunciation: "Women" /ˈwɪmɪn/
The word "women" deserves special attention because it trips up even advanced English learners. Here is what makes it so tricky:
- The spelling is misleading. The "o" in "women" is pronounced /ɪ/ (like the "i" in "win"), not /ʊ/ as in the singular "woman."
- The second syllable also changes. In "woman" it is /ən/ (a schwa), but in "women" it becomes /ɪn/.
- It sounds like "wimin." If you say it naturally and quickly, "women" rhymes with "swimmin'."
Practice tip: Say "win" and then add "min" after it. That gives you the natural flow of /ˈwɪmɪn/.
Common Pronunciation Mistakes
Mistake 1: Adding -s to irregular plurals
Never say "feets," "teeths," "childrens," or "mices." These words already are plural. Adding -s makes a double plural, which does not exist in English.
Mistake 2: Pronouncing "women" like "woman"
Remember: woman = /ˈwʊmən/ (with /ʊ/ like "book") and women = /ˈwɪmɪn/ (with /ɪ/ like "win"). The first vowel sound is the key difference.
Mistake 3: Using regular plural pronunciation for zero plurals
Words like "sheep" and "deer" do not change at all. Saying "sheeps" or "deers" sounds unnatural to native speakers.
Practice Sentences
Read these sentences aloud, paying special attention to the irregular plural pronunciations:
- The children lost two teeth each this year.
- We saw geese and deer near the lake.
- The women put their feet in the cold water.
- Three mice ran across the floor while the men were eating.
- There are beautiful cacti and fish in the aquarium.
- These natural phenomena attracted many sheep farmers to the area.
Memory Tips
- Foot → Feet, Goose → Geese, Tooth → Teeth: All three follow the same pattern. The /uː/ sound becomes /iː/. Think of it as the "oo-to-ee" group.
- Man → Men: The vowel gets slightly higher. Think "a to e" in both spelling and sound.
- Mouse → Mice: The "ow" diphthong becomes the "eye" diphthong. Think of a mouse saying "ow!" turning into mice saying "eye!"
- Woman → Women: The "oo" sound becomes an "ih" sound. Focus on the first syllable: "wuh" → "wih."
- Zero plurals (sheep, fish, deer): These are all animals. Just remember that some animals refuse to change!