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 -es, or -s if the singular already ends in -e:

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/ (sometimes) 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/

Phonologically, these rules are sufficient to describe most English plurals. However, certain complications arise in the spelling of certain plurals, as described below.