Grammatical Number - Overview

Overview

Most languages of the world have formal means to express differences of number. One widespread distinction, found in English and many other languages, involves a simple two-way number contrast between singular and plural (car/cars, child/children, etc.). Discussion of other more elaborate systems of number appears below.

Grammatical number is a morphological category characterized by the expression of quantity through inflection or agreement. As an example, consider the English sentences below:

That apple on the table is fresh.

Those two apples on the table are fresh.

The number of apples is marked on the noun—"apple" singular number (one item) vs. "apples" plural number (more than one item)—on the demonstrative, "that/those", and on the verb, "is/are". Note that, especially in the second sentence, all this information can seem redundant, since quantity is already indicated by the numeral "two".

A language has grammatical number when its nouns are subdivided into morphological classes according to the quantity they express, such that:

1. Every noun belongs to a unique number class. (Nouns are partitioned into disjoint classes by number.)
2. Noun modifiers (such as adjectives) and verbs have different forms for each number class and must be inflected to match the number of the nouns to which they refer. (Number is an agreement category.)

This is the case in English: every noun is either singular or plural (a few, such as "fish", can be either, according to context), and at least some modifiers of nouns—namely the demonstratives, the personal pronouns, the articles, and verbs—are inflected to agree with the number of the nouns to which they refer: "this car" and "these cars" are correct, while "*this cars" or "*these car" are ungrammatical and, therefore, incorrect. Only count nouns can be freely used in the singular and in the plural. Mass nouns, like "wine", "silverware", and "wisdom", are normally used in only the singular. Many languages distinguish between count nouns and mass nouns.

Not all languages have number as a grammatical category. In those that do not, quantity must be expressed either directly, with numerals, or indirectly, through optional quantifiers. However, many of these languages compensate for the lack of grammatical number with an extensive system of measure words.

There is a hierarchy among number categories: no language distinguishes a trial unless having a dual, and no language has dual without a plural.