Importance ★★
Discussion
By far, the most common type of plural formation in English involves simply adding an -s to a singular noun:
- book, books
- house, houses
If the singular noun already ends in -s, you add -es (or -ses) to form the plural:
- boss, bosses
- bus, buses
- gas, gases (or sometimes ‘gasses’)
Sometimes, but rarely, plural formation with an -s changes the spelling of the noun slightly:
- potato, potatoes
- hobby, hobbies
- soliloquy, soliloquies
In some cases, plural formation affects how a word is pronounced.
Voicing audible but not reflected in writing:
mouth (voiceless), mouths (voiced)
Voicing audible and reflected in writing:
- knife (voiceless), knives (voiced)
- BUT: belief (voiceless), beliefs (voiceless)
- life (voiceless), lives (voiced)
- BUT: still life (voiceless), still lifes (voiceless)
There are, however, some nouns that do not conform to the -s model at all. Below are various types of irregular plural formation and some examples:
Vowel change, e.g.:
- foot, feet
- mouse, mice
- woman, women
Zero plural, e.g.:
- fish, fish
- series, series
- sheep, sheep
It should also be noted that some words are always plural, even though they have no visible plural form:
- people (we talk about one person but in the plural, people is more common than persons)
- police (if we are talking about the police, we always do so in the plural; otherwise we say policeman or police officer)
The plural form of some words is a clue to the their etymological roots, such as the Germanic -en:
- child, children
- ox, oxen
Many English words come from Greek or Latin, which is reflected in their plural forms:
- addendum, addenda
- alumna (feminine), alumnae
- alumnus (masculine), alumni
- analysis, analyses
- antenna, antennae
- appendix, appendices
- corpus, corpora
- criterion, criteria
- curriculum, curricula
- formula, formulae (formulas)
- medium, media
- phenomenon, phenomena
- stimulus, stimuli
Summary
Although there are relatively few irregular nouns in English, there are many different categories to be aware of.
Further Discussion
In English, the morpheme -s serves a number of functions. When attached to a noun, it indicates plural. However, when attached to a verb, it indicates agreement with a third-person singular subject:
- he/she/it talks
Together with an apostrophe, -s is also used to indicate the genitive case—that is, a possessive:
- Harry’s Bar
Confusingly, the plural of letters (such as A, B, and C) is usually formed with ‘s:
- Dot the I’s and cross the T’s.
Similarly, the plural of acronyms and decades is formed either with or without an apostrophe:
- DVDs (or DVD’s), CEOs (or CEO’s), PCs (or PC’s)
- the 1930s (or the 1930’s), the 2000s (or the 2000’s)
Note, however, that English never forms plurals or genitives using a colon (as happens in Swedish):
- DVDs (not DVD:s)
Another source of confusion is the fact that sometimes, -s can be both plural and genitive at the same time. The genitive of a plural noun is indicated by an apostrophe following the plural -s:
- He tried to sell his parents’ car.
Avoid unnecessary confusion by placing the apostrophe in the accurate position. Compare the following sentences:
- He did not consider his girlfriend’s feelings.
- He did not consider his girlfriends’ feelings.
In any situation in which the latter sentence is accurate grammatically, it is likely also to be accurate factually.