Irregular plural nouns can be tricky for English learners because they don’t follow the standard rules of adding “-s” or “-es” to form the plural. Understanding these exceptions is crucial for accurate and fluent communication.
This guide provides a detailed exploration of irregular plural nouns, including their definitions, types, usage rules, common mistakes, and practice exercises. Whether you’re a beginner or an advanced learner, this comprehensive resource will help you master this essential aspect of English grammar and improve your overall language proficiency.
Table of Contents
- Definition of Irregular Plural Nouns
- Structural Breakdown
- Types or Categories of Irregular Plural Nouns
- Examples of Irregular Plural Nouns
- Usage Rules
- Common Mistakes
- Practice Exercises
- Advanced Topics
- FAQ
- Conclusion
Definition of Irregular Plural Nouns
Irregular plural nouns are nouns that do not form their plural by adding the standard suffixes “-s” or “-es” to the singular form. Unlike regular nouns, which follow a predictable pattern (e.g., cat becomes cats, box becomes boxes), irregular nouns have unique plural forms that must be memorized. These nouns often have historical or linguistic reasons for their irregularity, stemming from Old English or other languages from which English has borrowed.
The function of irregular plural nouns is the same as that of regular plural nouns: to indicate that there is more than one of the noun being referred to. However, their irregular formation sets them apart and requires specific attention to ensure correct usage.
These nouns are found in all contexts of English communication, from everyday conversation to formal writing, making their mastery essential for effective language use.
Structural Breakdown
The structural breakdown of irregular plural nouns reveals that there isn’t a single, unifying rule governing their formation. Instead, they exhibit a variety of patterns and exceptions. Some change internal vowels (e.g., foot to feet), while others undergo more significant transformations (e.g., child to children). Some nouns borrowed from other languages retain their original plural forms (e.g., criterion to criteria). The lack of a consistent pattern necessitates individual learning of each irregular noun.
Understanding the etymology of some irregular nouns can sometimes shed light on their plural forms. For example, many nouns of Greek or Latin origin follow the pluralization rules of those languages.
However, this is not always the case, as some have been Anglicized over time. Therefore, while etymology can be helpful, it’s not a foolproof method for predicting the plural form.
Types or Categories of Irregular Plural Nouns
Nouns with No Change in Plural Form
Some nouns remain the same in both their singular and plural forms. These nouns often refer to animals, fish, or units of measurement.
It’s important to note that context usually clarifies whether the noun is singular or plural.
Nouns with Internal Vowel Change
This is a common type of irregular plural where the vowel sound within the word changes to indicate plurality. This pattern is often derived from older forms of English.
Nouns with Irregular Endings
These nouns change their endings in unpredictable ways to form the plural. This category includes some of the most commonly encountered irregular plurals.
Nouns of Foreign Origin
English has borrowed many words from other languages, and some of these retain their original plural forms. These are often Latin or Greek in origin.
Irregular Compound Nouns
Compound nouns can also have irregular plural forms, often based on the most significant word within the compound.
Examples of Irregular Plural Nouns
Here are some examples of irregular plural nouns, categorized by their type. This extensive list will help you familiarize yourself with the different patterns and exceptions.
Nouns with No Change in Plural Form
These nouns maintain the same form whether singular or plural. The context determines the number.
| Singular | Plural | Example Sentence |
|---|---|---|
| Sheep | Sheep | I saw a sheep in the field. / There were many sheep grazing. |
| Fish | Fish (or Fishes) | I caught a fish yesterday. / We saw several fish swimming. / There are many different fishes in the aquarium (referring to different species). |
| Deer | Deer | A deer ran across the road. / Many deer inhabit the forest. |
| Swine | Swine | The farmer owns a swine. / The farmer owns many swine. |
| Aircraft | Aircraft | That is a military aircraft. / There were several aircraft on the runway. |
| Spacecraft | Spacecraft | The spacecraft launched successfully. / Several spacecraft are orbiting Earth. |
| Salmon | Salmon | I ordered salmon for dinner. / The river is full of salmon this season. |
| Trout | Trout | He caught a trout in the stream. / They caught many trout during their fishing trip. |
| Cod | Cod | I bought some cod from the market. / The fishermen caught a lot of cod today. |
| Offspring | Offspring | The bird protected its offspring. / The family has many offspring. |
| Series | Series | This is a new TV series. / They watched several series over the weekend. |
| Species | Species | The scientist studied a rare species of beetle. / There are many different species of birds in the rainforest. |
| Means | Means | This is a means of transportation. / They explored various means of achieving their goals. |
| Headquarters | Headquarters | The company’s headquarters is in New York. / The military headquarters are located in the capital. |
| Gallows | Gallows | The gallows stood ominously in the town square. / The gallows were used for public executions. |
| Crossroads | Crossroads | He stood at a crossroads in his life. / The city has many busy crossroads. |
| Works | Works | The factory works day and night. / The city has many industrial works. |
| Barracks | Barracks | The soldier returned to the barracks. / The military barracks were filled with new recruits. |
| Corps | Corps | He joined the Marine Corps. / Several corps participated in the military exercise. |
| Swiss | Swiss | He is Swiss. / Many Swiss live in the mountains. |
Nouns with Internal Vowel Change
These nouns change the vowel sound within the word to form the plural.
| Singular | Plural | Example Sentence |
|---|---|---|
| Foot | Feet | I hurt my foot playing soccer. / My feet are tired after walking all day. |
| Tooth | Teeth | I have a sore tooth. / She brushed her teeth. |
| Goose | Geese | A goose flew over the lake. / A flock of geese landed in the field. |
| Man | Men | A man walked into the store. / Several men were waiting in line. |
| Woman | Women | A woman gave a speech. / The women organized a protest. |
| Louse | Lice | The child had a louse in their hair. / The children had lice. |
| Mouse | Mice | A mouse ran across the floor. / The cats chased the mice. |
| Dwarf | Dwarfs (or Dwarves) | The story featured a dwarf. / The seven dwarfs lived in the forest. / The mythological stories described dwarves. |
| Brother | Brothers (or Brethren) | I have one brother. / I have two brothers. / The religious brethren gathered for prayer. |
| Woman | Women | I saw a woman at the store. / There were many women at the conference. |
| Person | People | One person is allowed. / Many people attended the concert. |
| Penny | Pennies (or Pence) | I found a penny on the ground. / I have a few pennies in my pocket. / The price is 50 pence. |
| Die | Dice | He rolled a die in the game. / They rolled the dice to start the game. |
| Ox | Oxen | The farmer used an ox to plow the field. / The farmer used two oxen to plow the field. |
| Child | Children | The child played in the park. / The children played together. |
| Syllabus | Syllabi (or Syllabuses) | The professor handed out the syllabus. / The professor handed out the syllabi. / The professor handed out the syllabuses. |
| Curriculum | Curricula (or Curriculums) | The school updated its curriculum. / The schools updated their curricula. / The schools updated their curriculums. |
| Genus | Genera | This plant belongs to a specific genus. / These plants belong to different genera. |
| Formula | Formulae (or Formulas) | He used a complex formula to solve the problem. / He used complex formulae to solve the problems. / He used complex formulas to solve the problems. |
| Index | Indices (or Indexes) | Check the index for the topic. / Check the indices for the topics. / Check the indexes for the topics. |
Nouns with Irregular Endings
These nouns form their plurals with unique and often unpredictable ending changes.
| Singular | Plural | Example Sentence |
|---|---|---|
| Thesis | Theses | She wrote a brilliant thesis. / They presented their theses at the conference. |
| Analysis | Analyses | The analysis revealed important data. / The analyses provided valuable insights. |
| Crisis | Crises | The country faced an economic crisis. / The country faced several economic crises. |
| Diagnosis | Diagnoses | The doctor made a quick diagnosis. / The doctors offered different diagnoses. |
| Oasis | Oases | They found an oasis in the desert. / They found several oases during their journey. |
| Axis | Axes | The Earth rotates on its axis. / The graph has two axes. |
| Basis | Bases | The argument had no basis in fact. / The arguments had no bases in fact. |
| Phenomenon | Phenomena | The aurora borealis is a beautiful phenomenon. / The northern lights are natural phenomena. |
| Criterion | Criteria | Meeting the criterion is essential. / Meeting the criteria is essential. |
| Datum | Data | This is important datum. / This is important data. |
| Addendum | Addenda (or Addendums) | The report had an addendum. / The report had several addenda. / The report had several addendums. |
| Memorandum | Memoranda (or Memorandums) | The boss sent a memorandum. / The boss sent several memoranda. / The boss sent several memorandums. |
| Bureau | Bureaux (or Bureaus) | He works for the government bureau. / He works for the government bureaux. / He works for the government bureaus. |
| Tempo | Tempi (or Tempos) | The music had a fast tempo. / The music had varying tempi. / The music had varying tempos. |
| Virtuoso | Virtuosi (or Virtuosos) | He is a piano virtuoso. / There were several virtuosi performing. / There were several virtuosos performing. |
| Larva | Larvae | The larva feeds on leaves. / The larvae feed on leaves. |
| Alumna | Alumnae | She is an alumna of the university. / The alumnae gathered for a reunion. |
| Alumnus | Alumni | He is an alumnus of the university. / The alumni gathered for a reunion. |
| Automaton | Automata (or Automatons) | The robot was an automaton. / The exhibition featured several automata. / The exhibition featured several automatons. |
| Cherub | Cherubim (or Cherubs) | The painting depicted a cherub. / The painting depicted several cherubim. / The painting depicted several cherubs. |
Nouns of Foreign Origin
These nouns, often from Latin or Greek, retain their original plural forms.
| Singular | Plural | Example Sentence |
|---|---|---|
| Radius | Radii | The radius of the circle is 5 cm. / The radii of the circles are different. |
| Stimulus | Stimuli | The bright light was a stimulus. / The bright lights were strong stimuli. |
| Focus | Foci (or Focuses) | The focus of the study was on climate change. / The foci of the study were on different aspects of climate change. / The focuses of the study were on different aspects of climate change. |
| Fungus | Fungi | The fungus grew on the tree. / The fungi grew on the tree. |
| Nucleus | Nuclei | The nucleus of the cell is important. / The nuclei of the cells are important. |
| Cactus | Cacti (or Cactuses) | The cactus survives in the desert. / The cacti survive in the desert. / The cactuses survive in the desert. |
| Millennium | Millennia (or Millenniums) | The new millennium began in 2000. / The millennia have seen many changes. / The millenniums have seen many changes. |
| Automaton | Automata (or Automatons) | The robot was an automaton. / The robots were automata. / The robots were automatons. |
| Apex | Apices (or Apexes) | The apex of the mountain was covered in snow. / The apices of the mountains were covered in snow. / The apexes of the mountains were covered in snow. |
| Vertex | Vertices (or Vertexes) | The vertex of the triangle is important. / The vertices of the triangle are important. / The vertexes of the triangle are important. |
| Matrix | Matrices (or Matrixes) | The matrix was complex. / The matrices were complex. / The matrixes were complex. |
| Appendix | Appendices (or Appendixes) | The book had an appendix. / The book had several appendices. / The book had several appendixes. |
| Seraph | Seraphim (or Seraphs) | The painting depicted a seraph. / The painting depicted several seraphim. / The painting depicted several seraphs. |
| Nebula | Nebulae (or Nebulas) | The telescope captured an image of a nebula. / The telescope captured images of several nebulae. / The telescope captured images of several nebulas. |
| Ultimatum | Ultimata (or Ultimatums) | The negotiator issued an ultimatum. / The negotiator issued several ultimata. / The negotiator issued several ultimatums. |
| Erratum | Errata | The book contained an erratum. / The book contained several errata. |
| Gymnasium | Gymnasia (or Gymnasiums) | The school has a new gymnasium. / The school has new gymnasia. / The school has new gymnasiums. |
| Stadium | Stadia (or Stadiums) | The stadium was packed with fans. / The stadia were packed with fans. / The stadiums were packed with fans. |
| Auditorium | Auditoria (or Auditoriums) | The auditorium was filled with people. / The auditoria were filled with people. / The auditoriums were filled with people. |
| Quantum | Quanta | The physicist studied the quantum. / The physicist studied the quanta. |
Usage Rules
The primary rule for using irregular plural nouns is to memorize their correct plural forms. There are no shortcuts, and relying on the regular “-s” or “-es” ending will often result in incorrect grammar.
Context is also important, especially for nouns that do not change in the plural. Pay attention to the surrounding words and sentence structure to determine whether the noun is singular or plural.
When using nouns of foreign origin, be aware that some have both the original foreign plural and an Anglicized plural form. While both may be acceptable, it’s important to be consistent within a piece of writing.
For example, you can use either “formulas” or “formulae” as the plural of “formula,” but avoid switching between the two in the same document.
For compound nouns, the plural is usually formed by pluralizing the main noun in the compound. For example, “passerby” becomes “passersby.” However, there are exceptions, such as “attorney general,” which becomes “attorneys general.” When in doubt, consult a dictionary.
Common Mistakes
One of the most common mistakes is applying the regular pluralization rules to irregular nouns. For example, saying “foots” instead of “feet” or “childs” instead of “children.” Another frequent error is using the singular form when the plural is required, especially with nouns that do not change in the plural (e.g., saying “one sheep” but also “two sheep” instead of “two sheeps”).
Another common mistake involves nouns of foreign origin. Learners may incorrectly Anglicize the plural form when the original form is still preferred (e.g., saying “cactuses” instead of “cacti”).
Conversely, they may use the foreign plural form incorrectly in contexts where the Anglicized form is more common (e.g., using “formulae” in a general science context instead of “formulas”).
Here are some examples of common mistakes and their corrections:
| Incorrect | Correct | Explanation |
|---|---|---|
| I saw two sheeps in the field. | I saw two sheep in the field. | “Sheep” does not change in the plural. |
| The childs were playing. | The children were playing. | The plural of “child” is “children.” |
| I have two foots. | I have two feet. | The plural of “foot” is “feet.” |
| The mouses ran away. | The mice ran away. | The plural of “mouse” is “mice.” |
| The criterions were met. | The criteria were met. | The plural of “criterion” is “criteria.” |
| The analysiss was thorough. | The analyses were thorough. | The plural of “analysis” is “analyses.” |
| The phenomenonons were studied. | The phenomena were studied. | The plural of “phenomenon” is “phenomena.” |
| The alumnis gathered. | The alumni gathered. | The plural of “alumnus” is “alumni.” |
| The syllabus’ were updated. | The syllabi were updated. | The plural of “syllabus” is “syllabi” or “syllabuses.” |
| The matrixes were complex. | The matrices were complex. | The plural of “matrix” is “matrices” or “matrixes.” |
Practice Exercises
Test your understanding of irregular plural nouns with these practice exercises. Fill in the blanks with the correct plural form of the noun in parentheses.
Exercise 1: Fill in the Blanks
- The farmer had many (sheep) ___________ in the field.
- The dentist examined my (tooth) ___________ carefully.
- Several (goose) ___________ were swimming in the pond.
- The (child) ___________ were playing in the park.
- The scientist studied different (species) ___________ of insects.
- The (analysis) ___________ of the data revealed interesting results.
- The museum displayed several (phenomenon) ___________ of nature.
- The (alumnus) ___________ of the university gathered for a reunion.
- The (criterion) ___________ for the award were very strict.
- The (cactus) ___________ thrived in the desert climate.
Answer Key:
- sheep
- teeth
- geese
- children
- species
- analyses
- phenomena
- alumni
- criteria
- cacti (or cactuses)
Exercise 2: Correct the Errors
Identify and correct the errors in the following sentences. If the sentence is correct, write “Correct.”
- I saw two deers in the woods.
- The childs were happy.
- My foots hurt after the long walk.
- The mouses were eating the cheese.
- The criterions were clearly defined.
- The thesis’ were well-researched.
- The alumnis donated generously.
- The syllabus were updated.
- The matrixes were complex.
- There were many fishs in the lake.
Answer Key:
- I saw two deer in the woods.
- The children were happy.
- My feet hurt after the long walk.
- The mice were eating the cheese.
- The criteria were clearly defined.
- The theses were well-researched.
- The alumni donated generously.
- The syllabi/syllabuses were updated.
- The matrices/matrixes were complex.
- There were many fish in the lake.
Exercise 3: Choose the Correct Plural Form
Select the correct plural form of the noun in parentheses:
- The professor discussed several (analysis / analyses) in the lecture.
- The (child / children) played happily in the yard.
- The zoo has a variety of (species / specieses) of birds.
- I need to brush my (tooth / teeth) before bed.
- The farmer counted his (sheep / sheeps) in the pen.
- The scientist conducted several (experiment / experiments) in the lab.
- The (woman / women) organized a community event.
- Many (person / people) attended the concert.
- The (mouse / mice) scurried across the floor.
- The (thesis / theses) were presented at the conference.
Answer Key:
- analyses
- children
- species
- teeth
- sheep
- experiments
- women
- people
- mice
- theses
Advanced Topics
Archaic Plurals
Some irregular plural forms are considered archaic and are rarely used in modern English. These forms often reflect older grammatical patterns and pronunciations that have fallen out of common usage.
While understanding these forms can be helpful for reading older texts, it’s generally best to avoid using them in contemporary writing and speech.
Double Plurals
A double plural occurs when a noun is pluralized in two different ways, often resulting in an incorrect or humorous effect. This can happen when learners mistakenly add both an irregular plural ending and the regular “-s” or “-es” suffix.
For example, saying “childrens” instead of “children” is a double plural.
Collective Nouns with Irregular Plurals
Collective nouns refer to a group of individuals as a single unit (e.g., team, family, committee). While most collective nouns take a singular verb, they can sometimes take a plural verb if the focus is on the individual members of the group rather than the group as a whole. When dealing with irregular plural collective nouns, it’s important to consider both the form of the noun and the intended meaning of the sentence.
FAQ
- Why do irregular plural nouns exist?
Irregular plural nouns exist due to the historical development of the English language. Many of these nouns come from Old English or other languages, which had different pluralization rules than modern English. Over time, these irregular forms have been preserved, while regular pluralization rules have evolved.
- Is it acceptable to use the regular “-s” ending for irregular nouns?
In most cases, it is not acceptable to use the regular “-s” ending for irregular nouns. Doing so will result in grammatically incorrect sentences. However, there are some exceptions, where both the irregular and regular plural forms are accepted, although the irregular form is often preferred.
- How can I memorize irregular plural nouns?
Memorizing irregular plural nouns requires practice and repetition. Flashcards, quizzes, and using the nouns in context can be helpful strategies. It’s also beneficial to understand the different categories of irregular plurals (e.g., vowel changes, foreign origins) to identify patterns and make memorization easier.
- Are there any patterns in irregular plural nouns that can help me learn them?
Yes, there are some patterns that can help. For example, many nouns with internal vowel changes follow similar patterns (e.g., foot/feet, tooth/teeth). Similarly, many nouns of Latin or Greek origin follow the pluralization rules of those languages. Recognizing these patterns can make learning irregular plurals more manageable.
- What should I do if I’m unsure of the plural form of a noun?
When in doubt, consult a dictionary. A good dictionary will provide the correct plural form of the noun, as well as any alternative forms that may be acceptable.
- Are there any regional variations in the use of irregular plural nouns?
While the
cultural context and origin of the word can sometimes influence usage, this is a more advanced nuance of language learning.
Conclusion
Mastering irregular plural nouns is essential for achieving fluency and accuracy in English. While these nouns may seem challenging at first, understanding their types, usage rules, and common mistakes can greatly improve your language skills.
By studying the examples provided, practicing the exercises, and consulting reliable resources, you can confidently use irregular plural nouns in your writing and speech. Embrace the irregularities of the English language, and continue to expand your vocabulary and grammatical knowledge.