Irregular plural nouns are words that don’t follow the typical pattern of adding -s or -es to form their plural forms, instead changing in unique ways. The regular noun plural in the English language is formed by adding the suffix -s or, where necessary, -es to the singular form of the noun. This regular plural formation has its origins in the Germanic languages, specifically Old English, which was spoken in England from the 5th to the 11th centuries.

Old English had a complex system of noun declensions with various grammatical cases, and different noun endings for singular and plural forms. However, over time, as the language evolved, many of these distinct noun endings were simplified or lost. The regular plural form with -s, or -es, emerged as a simplification of the Old English plural forms.

This suffix for regular plural nouns can be traced back to the Old English weak noun declension, which used -as or -es endings for plural forms. This declension pattern gradually became more prevalent until, eventually, it was the standard way to form plurals in both Middle English and Modern English.

However, over the years, the British Isles were also influenced by many other languages, the invasion and rule of the French from 1066, as well as the Latin influence on the language of education and religion ever since the Roman occupation of Britain from 43 – 410 AD. For quite some time, in the Middle English period, England was trilingual and the English that ultimately came to dominate the other languages and take over the language of the church, education and politics was greatly affected by its contact with French and Latin. It is this mixture of influences that gives English somewhat more irregular lexical and grammatical occurrences than most Germanic or Romance languages.

The following is a comprehensive list of nouns in English that take an irregular plural formation. Irregular plurals are nouns that have either preserved their older forms from Old English or have been influenced by other languages.

Nouns are naming words for things, objects, concepts, people or places. For more on nouns and other word classes, please refer to the post on parts of speech.

a small boat on stormy waters

Spellings that take plurals other than -s

Often words that end in -s, -ss, -zz, -x, -ch or -sh need the suffix -es rather than simply -s. The following are some examples of these.

  • box = boxes
  • branch = branches
  • bush = bushes
  • speech = speeches

Furthermore, words that end in -o frequently, but not always, form their plural by adding the suffix -es:

  • potato = potatoes
  • tomato = tomatoes
  • hero = heroes
  • echo = echoes
  • logo = logos
  • solo = solos
  • ratio = ratios
  • studio = studios

Words that end in -y usually drop the -y and add -ies:

  • authority = authorities
  • duty = duties
  • fairy = fairies
  • nationality = nationalities
  • history = histories
  • spy = spies

Irregular plurals

The plurals given here are the official, historically-correct plurals. The initials in brackets show the linguistic origins of the words. However, bear in mind that it can seem odd in normal conversation to talk about octopodes and would be perfectly acceptable to talk about octopuses! There is a fine balance that needs to be sought with some words, in particular academic words originating from the Latin or Greek, between knowing what is correct and being pedantic! Language use always needs to take into account whether one is participating in social writing and conversation or academic writing and speech.

Abbreviations:

  • Fr = French
  • Grk = Greek
  • It = Italian
  • Ln = Latin
  • OE = Old English

Keep in mind that much research into the origins of words is speculative and the given word origins are generalised. For further details, please see the references consulted in the bibliography.

A

addendum = addenda (Ln)

aircraft = aircraft (Modern)

alga = algae (Ln)

alumna = alumnae (Ln)

alumnus = alumni (Ln)

analysis = analyses (Ln)

antenna = antennae (Ln)

antithesis = antitheses (Grk)

apex = apices (Ln)

appendix = appendices (Ln)

atrium = atria (Ln)

axis = axes (Ln)

B

bacillus = bacilli (Ln)

bacterium = bacteria (Grk)

basis = bases (Grk)

beau = beaux (Fr)

bison = bison (Ln)

brother = brethren (OE)

bureau = bureaux (Fr)

C

cactus = cacti (Ln)

chateau = chateaux (Fr)

child = children (OE)

cod = cod (OE)

codex = codices (Ln)

concerto = concerti (It)

corpus = corpora (Ln)

crisis = crises (Grk)

criterion = criteria (Grk)

curriculum = curricula (Ln)

D

datum = data (Ln)

deer = deer (OE)

diagnosis = diagnoses (Grk)

die = dice (Ln)

dwarf = dwarves (OE)

E

elf = elves (OE)

ellipsis = ellipses (Grk)

erratum = errata (Ln)

F

fish = fish (OE)

focus = foci (Ln)

foot = feet (OE)

formula = formulae (Ln)

fungus = fungi (Ln)

G

genus = genera (Ln)

goose = geese (OE)

graffito = graffiti (It)

grouse = grouse (Fr?)

H

half = halves (OE)

hoof = hooves (OE)

hypothesis = hypotheses (Grk)

I

index = indices (Ln)

K

knife = knives (OE)

L

larva = larvae (Ln)

leaf = leaves (OE)

libretto = libretti (It)

life = lives (OE)

loaf = loaves (OE)

locus = loci (Ln)

louse = lice (OE)

M

man = men (OE)

matrix = matrices (Ln)

medium = media (Ln)

memorandum = memoranda (Ln)

minutia = minutiae (Ln)

moose = moose (extinct languages)

mouse = mice (OE)

N

nebula = nebulae (Ln)

nucleus = nuclei (Ln)

O

oasis = oases (Egyptian)

octopus = octopodes (octopuses) (Grk)

offspring = offspring (Modern)

opus = opera (Ln)

ovum = ova (Ln)

ox = oxen (OE)

P

parenthesis = parentheses (Grk)

person = people (Middle English/Old French)

phenomenon = phenomena (Grk)

phylum = phyla (Grk)

Q

quail = quail (Fr)

quiz = quizzes (Modern)

R

radius = radii (Ln)

referendum = referenda (Ln)

S

salmon = salmon (Ln)

scarf = scarves (OE)

self = selves (OE)

series = series (Ln)

sheep = sheep (OE)

shelf = shelves (OE)

shrimp = shrimp (Middle English)

species = species (Ln)

squid = squid (Possible Middle English)

stimulus = stimuli (Ln)

stratum = strata (Ln)

swine = swine (OE)

syllabus = syllabi (Ln)

symposium = symposia (Ln)

synopsis = synopses (Grk)

T

tableau = tableaux (Fr)

thesis = theses (Grk)

thief = thieves (OE)

tooth = teeth (OE)

trout = trout (OE)

tuna = tuna (Spanish)

V

vertebra = vertebrae (Ln)

vertex = vertices (Ln)

vita = vitae (Ln)

vortex = vortices (Ln)

W

wharf = wharves (OE)

wife = wives (OE)

wolf = wolves (OE)

woman = women (OE)

Nouns with no singular form

Additionally, there is a small number of nouns that do not have a singular form. These include the following,

  • Glasses
  • Jeans
  • Pants
  • Pyjamas
  • Scissors
  • Shorts
  • Spectacles
  • Trousers
  • Tweezers

Conclusion

Please note that irregular plural forms can vary depending on the specific noun and the context. Additionally, the usage of some irregular forms may differ between British English and other English dialects around the world.

Moreover, there is often confusion about words that have either Latin or Greek plural. For example, how would you say the plural of a hippopotamus? Very often a word that is regularly used in common English writing is erroneously written so often, and read by so many people as such over many years, that its erroneous spelling eventually becomes that of common usage and ultimately enters the dictionary as a viable alternative.

Languages constantly change and evolve and as English integrates foreign words into itself and makes them its own. This phenomenon also takes place with other world languages that integrate English words into their own tongues with similar spellings and sounds, yet slightly modified to fit their own spelling and pronunciation systems, and this is no different to what occurred in the English language.

If you have any irregular nouns to suggest or add, please do enter them in the comments.

Exercises to practise

Here are some exercises to consolidate your learning.

Irregular Plural Nouns

Using irregular plural nouns

1 / 20

What is the plural form of 'basis'?

2 / 20

Is 'criteria' singular or plural?

3 / 20

What is the singular form of 'series'?

4 / 20

What is the plural form of 'sheep'?

5 / 20

Is 'ellipsis' singular or plural?

6 / 20

What is the plural form of 'formula'?

7 / 20

What is the plural form of 'deer'?

8 / 20

What is the singular form of 'graffiti'?

9 / 20

What is the plural form of 'index'?

10 / 20

What is the plural form of 'leaf'?

11 / 20

What is the plural of 'matrix'?

12 / 20

What is the singular form of 'media'?

13 / 20

What is the plural of salmon?

14 / 20

Is 'phenomena' singular or plural?

15 / 20

I bought _______ today. (plural)

16 / 20

What is the singular form of 'offspring'?

17 / 20

What is the true plural form of 'octopus'?

18 / 20

What is the singular form of 'vertebrae'?

19 / 20

I bought _______ today. (singular)

20 / 20

What is the plural of 'woman'?

Your score is

The average score is 64%

0%

BIBLIOGRAPHY

Burton-Roberts, Noel. Analysing Sentences: An Introduction to English Syntax, 4th edn (Routledge, 2016)

Bryson, Bill. The Mother Tongue: English and how it got that way (Perennial, 2001)

Crystal, David. Spell it Out: The Singular Story of English Spelling (Profile Books, 2013)

Crystal, David. The Cambridge Encyclopedia of the English Language, 3rd edn (Cambridge University Press, 2019)

Cresswell, Julia. Oxford Dictionary of Word Origins (Oxford University Press, 2021)

Dreyer, Benjamin. Dreyer’s English: An Utterly Correct Guide to Clarity and Style (Penguin Random House, 2020)

Hewings, Martin, and others. Cambridge English Grammar and Vocabulary for Advanced (Cambridge University Press, 2015)

Huddleston, Rodney, and others. The Cambridge Grammar of the English Language (Cambridge University Press, 2002)

McWhorter, John. The Power of Babel: A Natural History of Language (Harper Perennial, 2003)

Parrott, Martin. Grammar for English Language Teachers, 2nd edn (Cambridge University Press, 2011)

Pinker, Steven. Words and Rules (W&N/ Science Masters, 2001)

Quirk, Randolph, and others. A Comprehensive Grammar of the English Language, reprint edn (Pearson, 2011)

Seely, John. Oxford A – Z of Grammar & Punctuation (Oxford University Press, 2020)

https://dictionary.cambridge.org/dictionary/english/

https://www.oed.com/

https://www.oxfordlearnersdictionaries.com/definition/english/

 

2 Comments

  1. This article provides a thorough and fascinating exploration of irregular plurals in the English language. It’s intriguing to learn about the historical origins and influences of other languages on English noun formations. The comprehensive list of irregular plurals showcases the diversity and complexity of language evolution. It’s amazing to see how some irregular forms become commonly accepted over time, reflecting the dynamic nature of the English language. This discussion sheds light on the intricacies of language and highlights the beauty of its constant adaptation. Thanks for sharing this informative and enlightening piece!

    • Hi Liam, thanks again for your wonderful comments. I’m so glad you found this a valuable article.

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