گرامر plurals

Regular plurals

The plural morpheme in English is suffixed to the end of most nouns. Regular English plurals fall into three classes, depending upon the sound that ends the singular form:

Where a singular noun ends in a sibilant sound —/s/, /z/, /ʃ/, /ʒ/, /tʃ/ or /dʒ/— the plural is formed by adding /ɨz/. The spelling adds -s, or -es if the singular already ends in -s:

kiss	kisses	/ˈkɪsɨz/
phase	phases	/ˈfeɪzɨz/
dish	dishes	/ˈdɪʃɨz/
massage	massages	/məˈsɑːʒɨz/ or /ˈmæsɑːʒɨz/
witch	witches	/ˈwɪtʃɨz/
judge	judges	/ˈdʒʌdʒɨz/

When the singular form ends in a voiceless consonant (other than a sibilant) —/p/, /t/, /k/, /f/ or /θ/— the plural is formed by adding /s/. The spelling adds -s:

lap	laps	/læps/
cat	cats	/kæts/
clock	clocks	/klɒks/
cuff	cuffs	/kʌfs/
death	deaths	/dɛθs/

For all other words (i.e. words ending in vowels or voiced non-sibilants) the regular plural adds /z/, represented orthographically by -s:

boy	boys	/bɔɪz/
girl	girls	/ɡɜrlz/
chair	chairs	/tʃɛərz/

Morphophonetically, these rules are sufficient to describe most English plurals. However, there are several complications introduced in spelling.

The -oes rule: most nouns ending in o preceded by a consonant also form their plurals by adding -es (pronounced /z/):

hero	heroes
potato	potatoes
volcano	volcanoes or volcanos

The -ies rule: nouns ending in a y preceded by a consonant usually drop the y and add -ies (pronounced /iz/). This is taught to many North American and British students with the mnemonic: "Change the y to i and add es":

cherry	cherries
lady	ladies

However, proper nouns (particularly those for people or places) ending in a y preceded by a consonant form their plurals regularly:

Germany	Germanys (as in The two Germanys were unified in 1990; this rule is commonly not adhered to as several book titles show; Sicilies and Scillies, rather than Sicilys and Scillys, are the standard plurals of Sicily and Scilly.)
Harry	Harrys (as in There are three Harrys in our office)

The rule does not apply to words that are merely capitalized common nouns:

P&O Ferries (from ferry)

Other exceptions include lay-bys and stand-bys.

Words ending in a y preceded by a vowel form their plurals regularly:

day	days
monkey	monkeys

(Money/Monies is an exception, but money can also form its plural regularly.

Almost-regular plurals

Many nouns of foreign origin, including almost all Italian loanwords, are exceptions to the -oes rule:

canto	cantos
homo	homos
photo	photos
zero	zeros
piano	pianos
portico	porticos
pro	pros
quarto (paper size)	quartos
kimono	kimonos

In Old and Middle English voiceless fricatives /f/, /θ/ mutated to voiced fricatives before a voiced ending. In some words this voicing survives in the modern English plural. In the case of /f/ changing to /v/, the mutation is indicated in the orthography as well; also, a silent e is added in this case if the singular does not already end with -e: