Most plural nouns follow predictable spelling rules. We teach children to add -s or -es, and they quickly learn patterns like:
cat → cats
box → boxes
baby → babies
However, English also includes a group of nouns that do not follow these standard rules. These are called irregular plural nouns, and they require a slightly different teaching approach.
Because these words appear frequently in both reading and writing, students benefit from early, consistent exposure. This guide will help parents and teachers explain irregular plurals clearly and teach them with confidence.
What are irregular plural nouns?
An irregular plural noun is a noun that does not form its plural by simply adding -s or -es. Instead, the word changes in a different way. Sometimes the vowel changes. Sometimes the ending changes. Occasionally, the word stays exactly the same.
Examples:
man → men
woman → women
child → children
tooth → teeth
foot → feet
mouse → mice
goose → geese
Unlike regular plurals, these forms must largely be memorized. However, grouping them by pattern makes them easier to teach and understand.
Common irregular plural patterns
Although irregular plurals seem random at first, many follow recognizable patterns. Teaching these patterns reduces frustration and helps students feel more confident.
Vowel change within the word
In this group, the middle vowel changes to form the plural. The ending does not follow the standard -s rule.
Examples:
man → men
foot → feet
tooth → teeth
goose → geese
This pattern is common enough that students can begin to notice similarities. When teaching, it helps to visually highlight the vowel change so children can clearly see what shifts between singular and plural.
Encourage students to say both forms aloud. Hearing the sound change reinforces spelling patterns.
-en ending
A small group of nouns form plurals by adding -en.
Examples:
child → children
ox → oxen
These are less common but appear often in reading. Because there are only a few nouns in this category, repetition and practice sentences are especially helpful.
Teachers may want to introduce these separately so students are not overwhelmed by too many patterns at once.
A side-note on teaching the plural word children: The word children doesn’t follow a spelling rule. It’s simply irregular and must be memorized.
When teaching it, show students the two-step change:
child
child + r
childr + en
children
Explain that the word changed over time in English. Long ago, the plural was childer, and later -en was added, creating children.
For students, a simple explanation works best:
“This word is old and special. We memorize it.”
Keeping the explanation brief prevents confusion and helps students accept it as an irregular form.
Same singular and plural form
Some nouns do not change at all when they become plural.
Examples:
sheep → sheep
deer → deer
fish → fish
This category often surprises students. They may try to add an -s automatically. Point out that the number in the sentence tells us whether the noun is singular or plural:
One deer is running.
Three deer are running.
Helping students notice subject-verb agreement strengthens understanding.
ou → i pattern
Some irregular plurals change ou to i.
Examples:
mouse → mice
louse → lice
Students often try to write mouses, so it is helpful to explicitly teach this pattern. Practice saying the pair aloud (mouse, mice) to reinforce both the sound and spelling change.
Remind students that there are only a couple of words in this group, so they should memorize them rather than try to apply the pattern to new words.
Completely different word
A few nouns form the plural by changing into an entirely different word. However, only person → people is truly a common everyday noun that becomes a totally different word.
Example:
person → people
This type must be memorized because it does not follow a visible pattern. Encourage students to use the plural form in complete sentences to strengthen retention.
How to teach irregular plural nouns effectively
Irregular plurals require a slightly different teaching approach than regular plurals. Instead of teaching one rule, focus on pattern recognition and repetition.
Step 1: review regular plural rules first
Before introducing irregular forms, ensure students understand:
Adding -s
Adding -es
Changing -y to -ies
When students clearly understand regular patterns, they are better able to recognize when a word does not follow the rule.
Step 2: introduce words in small groups
Avoid presenting a long list all at once. Instead:
Introduce 4–5 irregular nouns at a time.
Practice orally and in writing.
Use them in meaningful sentences.
Frequent short review sessions are more effective than one long lesson.
Step 3: use sorting and comparison activities
Sorting activities help students distinguish between regular and irregular plurals.
For example, students can sort:
Regular:
dogs
boxes
babies
Irregular:
men
oxen
mice
This comparison builds deeper understanding because students must think about why each word belongs in its category.
Practice activities for the classroom
Fill in the blank
Provide context to support understanding:
There are three _______ in the field. (sheep)
My two _______ hurt after the long walk. (feet)
Encourage complete sentences, not just single-word answers.
Sentence rewrite
Have students rewrite singular sentences into plural form:
The child is playing.
The children are playing.
This reinforces both plural forms and subject-verb agreement.
Matching game
Create matching cards with singular and plural forms:
mouse — mice
man — men
ox — oxen
Hands-on activities are particularly helpful for visual and kinesthetic learners.
Practice ideas for parents at home
Parents do not need elaborate worksheets to reinforce irregular plurals.
Simple conversation practice works well:
What is the plural of tooth?
If we see one goose with another goose, what do we say?
Encourage your child to use the word in a full sentence. This builds both grammar and speaking confidence.
Keep sessions short and positive. Five minutes of practice several times a week is more effective than one long drill session.
Common mistakes to watch for
Students often apply regular plural rules automatically. You may see:
mans
childs
foots
mouses
Instead of simply correcting the word, ask guiding questions:
Does this follow the regular rule?
Does it sound right when you say it aloud?
Encouraging self-correction builds long-term understanding.
Why irregular plural nouns matter
Irregular plural nouns appear frequently in early reading materials and classroom writing assignments. When students master these forms, they improve:
Spelling accuracy
Sentence fluency
Reading comprehension
Confidence in writing
Although these words must largely be memorized, structured practice and repeated exposure make them manageable and less intimidating.
