Forming Plurals of Irregular Nouns in English: Morphological, Spelling, and Pronunciation Changes

Unlike regular English nouns for which the plural morphological suffix is either -s or -es, irregular English nouns require vowel changes, consonant changes, or suffixation. For some common English nouns of Old English origin, the vowel undergoes an ablaut or vowel sound change. For example, the following chart identifies the singular and plural forms of some common irregular English nouns of Old English origin:

• Singular – Plural
• foot – feet
• louse – lice
• man – men
• mouse – mice
• person – people (also consonant sound change)
• tooth – teeth
• woman – women

For some other common English nouns of Old English origin, the plural morphological suffix is -en or -n. For example, the following chart identifies the singular and plural forms of some other common (and dialectal) irregular English nouns of Old English origin:

• Singular – Plural
• brother – brethren/brothers (archaic)
• child – children
• cow – kine/cows (archaic)
• eye – eyen/eyes (dialectal)
• ox – oxen
• house – housen/houses (dialectal)
• shoe – shoon/shoes (dialectal)

For other common English nouns often of Old English origin and referring to groups of animals, the plural form is identical to the singular form. For example, the following chart identifies the singular and plural forms of some more irregular English nouns:

• Singular – Plural
• bison – bison
• deer – deer
• moose – moose
• offspring – offspring
• salmon – salmon
• sheep – sheep
• species – species
• trout – trout

Unlike the plural forms of nouns of English origin, the plurals of nouns borrowed as loanwords from foreign languages often conserve the plural form from the original language. If the noun is of Latin origin and ends in a, change the a to an ae. For example, the following chart identifies the singular and plural forms of Latin loanwords ending in a:

• Singular – Plural
• alumna – alumnae
• formula – formula

If the noun is of Latin origin and ends in ex or ix, change the ex or ix to ices. For example, the following chart identifies the singular and plural forms of Latin loanwords ending in ex and ix:

• Singular – Plural
• index – indices
• matrix – matrices
• vertex – vertices

If the noun is of Latin origin and ends in is, change the is to an es. For example, the following chart identifies the singular and plural forms of Latin loanwords ending in es:

• analysis – analyses
• axis – axes
• crisis – crises
• testis – testes
• thesis – theses

For more rules for forming the plurals of foreign loanwords, please continue reading on page two.