Plural Form of Irregular Nouns

In English language learning, there are always exceptions to the rules. One of these exceptions is forming the plural of irregular nouns. Irregular nouns are words that do not follow the standard rules for forming plurals, such as adding -s or -es to the end of a noun. Instead, they require a change in spelling to conjugate their plural forms.

In this blog, we will look at some of the most common irregular nouns in English and how to form their plural forms.

What is the Plural Form of Irregular Nouns?

The plurality of a noun refers to more than one object or person. In English, the plural form of a noun is usually formed by adding -s or -es to the end of the word. However, some nouns do not follow this rule and require spelling changes to conjugate their plural forms. These are known as irregular nouns.

The table below shows the difference between the plural form of regular nouns and irregular nouns:

Type of Noun	Singular Form	Plural Form
Regular	– glass – pie – flower – cart – painting	– glasses – pies – flowers – carts – paintings
Irregular	– foot – knife – mouse – bacterium – loaf	– feet – knives – mice – bacteria – loaves

Plural Form of Irregular Nouns Rules

While capturing all the rules of forming the plural form of irregular nouns is tricky, some common rules can help you remember the correct plural form of most irregular nouns.

Here are the rules for conjugating irregular nouns in their plural forms:

Rule	Singular Form	Plural Form
If an irregular noun ends in ‘f’ or ‘fe,’ change it into the letter ‘v’ and add the suffix ‘-es.’	– wife – calf – dwarf – half – leaf	– wives – calves – dwarves – halves – leaves
If an irregular noun has a double ‘o’ in the middle, change it into a double ‘e’.	– foot – goose – tooth	– feet – geese – teeth
If an irregular noun ends in ‘an,’ change it into ‘en.’	– man – woman – gentleman	– men – women – gentlemen
If an irregular noun ends in ‘is,’ switch the letter ‘i’ into the letter ‘e.’	– synopsis – thesis – crisis – hypothesis – axis	– synopses – theses – crises – hypotheses – axes
If a Latin or Greek noun ends in “us,” change its last two letters into ‘i.’	– nucleus – fungus – cactus – syllabus – octopus	– nuclei – fungi – cacti – syllabi – octopi
If a Greek word ends in ‘on,’ change the last two letters into ‘a.’	– criterion – phenomenon	– criteria – phenomena
If an irregular noun ends in the letter ‘a,’ add the letter ‘e’ on its end. These irregular nouns can also have their regular plural form.	– formula – vertebra – antenna	– formulae or formulas – vertebrae or vertebras – antennae or antennas
If an irregular noun ends in ‘um,’ change the last two letters into ‘a.’	– memorandum – curriculum – addendum – bacterium – datum – erratum – medium – stratum – referendum – symposium	– memoranda – curricula – addenda – bacteria – data – errata – media – strata – referenda – symposia
Some irregular nouns completely change in spelling in their plural form.	– die – ox – mouse – child	– dice – oxen – mice – children
Some irregular nouns have the same singular and plural form.	– species – aircraft – tuna – series – bison – swine – deer	– species – aircraft – tuna – series – bison – swine – deer

Uncountable nouns like hair, rice, and wine are considered singular nouns. However, their plural forms are formed by adding a number and a form or unit of measurement.

Singular	Plural
hair	ten strands of hair
rice	seven cups of rice
wine	two bottles of wine
coffee	four cups of coffee
water	ten gallons of water
furniture	five pieces of furniture
clothing	three items of clothing
bread	six loaves/slices of bread

Examples of Plural Forms of Irregular Nouns

Here are fifteen sentences using the plural form of irregular nouns:

1. Marcius and I watched the geese fly in a V formation across the sky.

2. I need to buy two new knives for my kitchen.

3. We saw several deer in the forest this morning.

4. There were many cacti growing in the desert.

5. Gian needs two dice for the board game.

6. The children were playing with a pile of leaves.

7. We found a group of bacteria in the petri dish.

8. I bought three loaves of bread from the bakery.

9. Maya’s children are all successful in their fields of study.

10. The cats are trying to catch those mice scurrying around the barn.

11. My father and his friends were discussing the latest news.

12. You are not allowed to release ten memoranda in a day.

13. We saw several species of fish in the aquarium.

14. Harold used five media to create his artwork.

15. The data Fatima collected was helpful in her research.

Plural Form of Irregular Nouns Exercises with Answers

Complete the table below by providing the plural form of irregular nouns.

Singular	Plural
analysis	1.
forum	2.
stimulus	3.
nebula	4.
deer	5.

Answers

Singular	Plural
analysis	1. analyses
forum	2. fora
stimulus	3. stimuli
nebula	4. nebulae or nebulas
deer	5. deer

Plural Form of Irregular Nouns List

Singular Irregular Nouns	Plural Irregular Nouns
alumna	alumnae
amoeba	amoebae or amoebas
analysis	analyses
apex	apices or apexes
aquarium	aquaria or aquariums
basis	bases
bison	bison
bureau	bureaux or bureaus
cactus	cacti
château	chateaux or chateaus
child	children
codex	codices or codexes
crisis	crises
curriculum	curricula
datum	data
diagnosis	diagnoses
dictum	dicta or dictums
elf	elves
ellipsis	ellipses
erratum	errata
fish	fish
focus	foci
foot	feet
genus	gena
goose	geese
index	indexes
larva	larvae
leaf	leaves
man	men
moose	moose
mouse	mice
oasis	oases
ox	oxen
parenthesis	parentheses
person	people
phylum	phyla
radius	radii
self	selves
series	series
sheep	sheep
swine	swine
tableau	tableaux or tableaus
thief	thieves
tooth	teeth
trout	trout
tuna	tuna
vertex	vertices or vertexes
wolf	wolves
woman	women

Advice for ESL Students & English Language Learners

English grammar, like any language, is a complex subject to study. Understanding and applying grammar rules can be challenging, especially for English language learners. However, your success in learning the language is dependent on your learning plan.

First, know that there are different levels of language proficiency. Knowing your status allows you to align it with your study materials and learning strategy. To keep your motivation, select beginner-friendly materials instead of university textbooks when starting. In doing so, you will feel less intimidated by the topics you should learn.

Second, focus on the basics: nouns, verbs, adjectives, and adverbs. Learn how to use them correctly in sentences and understand their meaning. It will help you build a strong foundation for your English language learning journey. Divide those topics into subtopics and learn each concept and rule one by one.

Third, find a reliable source of learning materials. Online resources such as websites, blogs, and YouTube videos are mostly free. LillyPad’s blog, for example, is a great resource for English language learning materials. Additionally, you can find books and other printed materials in your local library or bookstore.

Fourth, practice speaking the language with native speakers or other English learners. It will help you understand how to use the language correctly in conversations and improve your pronunciation.

Finally, be patient with yourself and don’t give up. Learning a language takes time and effort, so set realistic goals and celebrate your achievements along the way.

Additionally, it is important for learners to properly understand plural form of compound nouns and nouns definition and examples.

Common Errors Made by English Learners

Learning a new language can be difficult, and English is no exception. Even experienced English learners make mistakes when speaking or writing in the language. Here are some of the most common mistakes made by English learners:

Common Mistake	Why it Happens	Correction	Examples
Adding ‘s’ or ‘es’ to the plural form of irregular nouns.	Learners likely carry the rule on pluralizing regular nouns with irregular nouns. This common mistake also happens when learners don’t familiarize themselves with or memorize irregular nouns.	After learning about regular nouns, familiarize yourself with irregular nouns. Note that the plural form of both differs. Hence, avoid adding ‘s’ or ‘es’ to the plural form of irregular nouns.	Incorrect: childrens mices radiis oxens Correct: children mice radii oxen “Peoples” and “fishes” are an exception to this rule. We use people when referring to more than one group or kind of people. The same applies to fishes.
Adding ‘s’ or ‘es’ to irregular unchanging nouns.	Unchanging nouns are tricky. Hence, some learners pluralize them by following the regular rule.	Since there are only a few unchanging irregular nouns, the best way to avoid this mistake is to memorize them.	Incorrect deer – deers barracks – barrackses bison – bisons  moose – mooses Correct deer – deer barracks – barracks bison – bison moose – moose

Learning Strategies and Best Practices for Plural Form of Irregular Nouns

A holistic approach to learning a language makes it easier to understand and remember. The five macro skills, reading, listening, viewing, speaking, and writing, should be developed and used in the learning process for better language acquisition. The table below lists activities you can do when learning linking verbs:

Learning Strategies
Reading	– Use flashcards to know basic English sight words and their meaning. – Search for material that contains translations of common expressions from your native language to English. – Select study materials appropriate for your language proficiency.
Listening	– Listen to an audiobook or a song and write what you hear to improve your retention of English words. – Compare and contrast two audio materials like TV ads and a speech. – Summarize a podcast, movie, audiobook, and other English audio materials.
Viewing	– Observe how native speakers speak and try to mimic it. – Watch English movies, interviews, and tutorials. – Use pictographs to learn and remember new words.
Speaking	– Join a community of English language learners and communicate with them to improve and gain feedback. – Integrate the language into your daily life and try to speak using English. – Participate in speech organizations (e.g. debate clubs, theatre groups)
Writing	– Write a journal of your learning journey in English. – Answer practice tests and create your own sentences. – Create a reflection essay on the media you watch or listen to.

Plural Form of Irregular Nouns Frequently Asked Questions