Irregular Plural Nouns

Learning Irregular Plural Nouns
Learning irregular plural nouns is an important step in mastering English grammar. While it requires memorization, recognizing the patterns and categories can help.

Main types of irregular plurals

1. Internal Vowel Change (Mutations):
   These plurals change a vowel sound within the word.
   foot → feet
   goose → geese
   man → men
   tooth → teeth
   woman → women
   

2. -en Plural:
   child → children
   ox → oxen
   

3. No Change:
   The singular and plural forms are identical. These are often related to animals or units of measurement.
   aircraft
   deer
   fish
   moose
   offspring
   series
   sheep
   species
   

4. Plurals from Latin or Greek:
   These words retain their original plural forms from Latin or Greek.
   -a to -ae (Latin):
   formula → formulae (or formulas)
   larva → larvae
   nebula → nebulae
   -us to -i (Latin):
   alumnus → alumni
   cactus → cacti
   focus → foci
   fungus → fungi
   nucleus → nuclei
   radius → radii
   stimulus → stimuli
   -on to -a (Greek):
   criterion → criteria
   phenomenon → phenomena
   

The following diagram shows some examples of irregular plurals. Scroll down the page for more examples.

 

Points to remember:

• Irregular plurals don’t follow the standard rules.
• Memorization is the primary way to learn them.
• Pay attention to context, as some words have different plural forms with different meanings.
• When in doubt, consult a dictionary.

Rules for forming plural of nouns
The most common way to form the plural of a noun is by adding “-s” to the end.
cat → cats
dog → dogs
book → books
Make plural nouns by adding s

Words ending in -s, -ss, -sh, -ch, -x, or -z: Add “-es” to form the plural.
This is because adding just “-s” would make the word difficult to pronounce.
bus → buses
dress → dresses
Make plural nouns by adding es

Words ending in consonant + -y: Change the “y” to “-ies”.
baby → babies
story → stories
Words ending in vowel + -y: Simply add “-s”.
boy → boys
day → days
Plural nouns for words ending in y

Words ending in -f or -fe: In many cases, change the “f” or “fe” to “-ves”. However, some words just add “-s”.
leaf → leaves
chief → chiefs
Plural nouns for words ending in f or fe

Words ending in -o: Generally add “-es,” but some words just add “-s.” There’s no perfect rule, so memorization is often necessary.
potato → potatoes
photo → photos
Plural nouns for words ending in o

Irregular Plurals:
Some nouns have irregular plural forms that don’t follow any of the above rules. These must be memorized.
man → men
child → children
foot → feet
ox → oxen
Nouns with the Same Singular and Plural Form:
Some nouns have the same form in both singular and plural.
sheep
deer
Irregular plural nouns

Irregular Plurals: A Rap Song
Irregular plurals don’t follow rules. You just need to learn them when you study in school.

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Irregular Plural Nouns
Some nouns don’t follow the usual rules of adding an -s, -es or -ies when they become plural. Some change a letter or become a different word completely. Some stay the same in their singular and plural forms

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Plural Nouns in English | Regular & Irregular Plural Nouns | Plurals Spelling
Regular nouns adding -s to the end.
Nouns ending in s, ch, sh, x, and z (adding -es to the end)
Nouns ending in f or fe (the -ves rule)
Nouns ending in a vowel + y (add -s to the end)
Nouns ending in a consonant + y (the -ies rule)
Nouns ending in a vowel + o (add -s to the end)
Nouns ending in a consonant + o (the -es rule)
Irregular nouns that do not end in s in their plural form (e.g. child)
Nouns that remain the same in singular and plural form (e.g. sheep)

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Plural Nouns
Plural Nouns, add -s	Plural Nouns, add -es	Words ending with y
Words ending with f or fe	Words ending with o	Irregular Plural Nouns
Summary of Plural Nouns

Other Digraphs
AR Sound	Er,Ir,Ur	OR Sound
Ar,Er,Ir,Or,Ur	Ou, Ow	Oi, Oy
OO Sound

Free Printable Worksheets for Consonant Digraphs

These worksheets focus on the consonant digraphs: ch, sh, th, qu and ng.

Printable Worksheets (Consonant Digraphs)
Learning "ch"	Learning "sh"
Learning "th"	Learning "qu"
Learning "ng"

Free Printable Worksheets for Digraphs

Printable Worksheets (EE, OO, OU, OI, AW)
EE Words	OO Words
OI Words	AW Words

Learn the sound of the letters

Learning Short Vowels

Short Vowels
Short A	Short E	Short I
Short O	Short U	Short Vowels

Learning Long Vowels

Long Vowels
Long A	Long E	Long I
Long O	Long U	Y (vowel)
Long Vowels	Short & Long Vowels

Compare Short & Long Vowels

Short & Long Vowels
Short & Long A	Short & Long E	Short & Long I
Short & Long O	Short & Long U

Learning Consonants

Consonants
Letter B	Hard C	Soft C
Letter D	Letter F	Hard G
Soft G	Letter H	Letter J
Letter K	Letter L	Letter M
Letter N	Letter P	Letter Q
Letter R	Letter S	Letter T
Letter V	Letter W	Letter X
Letter Y	Letter Z

Try the free Mathway calculator and problem solver below to practice various math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.

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