Most nouns make the plural with -s or -es. Some nouns have special plural forms. These are irregular plural nouns. You need to learn the singular form and the plural form together.

Some irregular plural nouns change a vowel in the middle of the word. The ending does not use -s. These forms are common in everyday English.

Word or Phrase	Definition
man → men	This noun changes the vowel a to e in the plural form.
woman → women	This noun changes the vowel in the middle in the plural form.
foot → feet	This noun changes oo to ee in the plural form.
tooth → teeth	This noun changes oo to ee in the plural form.
goose → geese	This noun changes oo to ee in the plural form.

Some irregular plural nouns take a different ending. They do not add only -s or -es. The whole plural form must be learned.

Word or Phrase	Definition
child → children	This noun adds -ren in the plural form.
person → people	This noun uses a different word in the plural form.
mouse → mice	This noun changes to a different ending in the plural form.

Some nouns have the same form in singular and plural. The noun does not change. The sentence shows if the meaning is one or more than one.

Word or Phrase	Definition
sheep	This noun stays the same in singular and plural.
fish	This noun often stays the same in singular and plural.
deer	This noun stays the same in singular and plural.

Irregular plural nouns are used after numbers greater than one and after quantity words like many, a few, and several. Same-form nouns also stay the same after these words. The noun form must match the quantity.

Rule
After numbers greater than one, use the plural form, as in two men or three children.
After many, a few, and several, use the plural form, as in many people or a few teeth.
With same-form nouns, the word does not change after a quantity, as in two sheep or several fish.

Irregular plural nouns take plural determiners and plural verbs. Use these, those, many, and few with plural nouns. Use plural verbs like are with irregular plural subjects.

Rule
Use plural determiners with irregular plural nouns, such as these men and those children.
Use plural verbs with irregular plural subjects, such as the women are and the people were.
Same-form plural nouns also take plural verbs, such as the sheep are and the fish were.

You can now recognize common irregular plural nouns and use them in sentences. You can use vowel-change plurals, new-ending plurals, and same-form plurals. You can also match them with quantities, determiners, and plural verbs.