English grammar - Roger Berry 2012

A2.3 The formation of plurals
A2 Nouns
Section A. Introduction

Plurals are formed from the singular form of nouns. Most plurals are formed regularly by the addition of -s or -es in writing (and replacing a final -y after a consonant with -ies), and by the addition of /-s/, /-z/ or /-iz/ in speech. Here are some examples of regular plurals:

cat/cats /-s/ dog/dogs /-z/

story/stories /-z/ watch/watches /-iz/

Note that the written and spoken additions do not always coincide; judges only has -s in spelling to show the plural, but adds /-iz/ in pronunciation. The rules are explained in the Website Reference A2.4.

Irregular plurals

You probably already know that a few nouns have irregular plurals. ’Irregular’ means that the form of the plural cannot be predicted from the singular. The most common are:

children (from child), feet (foot), men (man), mice (mouse), teeth (tooth), women (woman)

Then there are a number of words referring to animals that have a ’zero’ plural, for example sheep, deer. There are also a few nouns ending in -f or -fe which form their plural with -ves in writing, for example knife, leaf, life, thief, wife, wolf; in pronuncia­tion the /-f/ changes to /-vz/. See the Website Reference A2.5 for more examples of all of these types.

Words borrowed from foreign languages (typically Latin, Greek and French) are another source of irregular plurals. Here are some examples (singular/plural):

□ criterion/criteria

□ crisis/crises

□ curriculum/curricula

□ stimulus/stimuli

□ chateau/chateaux

See the Website Reference A2.6 for more coverage.

In addition there are a number of words that have two possible plurals, one regular and one irregular, for example hoofs/hooves. The Website Reference A2.7 has more examples.

Number does not only relate to nouns; it also affects pronouns (see B2) and verbs (see agreement in A8).