pluralization

Pluralization is the process by which nouns and other words are marked to refer to more than one entity. It is a key aspect of number morphology, and in many languages it affects agreement with verbs, adjectives, determiners, and pronouns.

In English, plural forms most often involve adding a suffix: -s or -es (dog/dogs; bus/buses). Some nouns change their internal vowels (man/men), or alter their endings (child/children). Others end in -y and change to -ies (party/parties). A number of words have irregular plurals (foot/feet, mouse/mice) or remain unchanged in both singular and plural form (sheep, deer). Some nouns are used mainly in the plural, such as scissors or trousers.

Across languages, plural formation varies: suffixes are common (German -e, -en, -er; Russian -ы/-и; Arabic broken plurals). Others rely on internal vowel changes or stem modifications. Some languages do not mark number on the noun itself and instead rely on determiners or numerals; for example, Mandarin Chinese uses a numeral plus a classifier before the noun and generally does not change the noun to mark plurality.

Pluralization has implications for syntax and semantics, including subject–verb agreement, quantity interpretation, and counting. In computational linguistics, pluralization is a concern for lemmatization, stemming, and morphological generation in natural language processing.