NUMBER. Countables have two numbers - the singular and the plural.
In Modern English the singular form of the nouns is a stem with a zero-inflexion.
The plural is formed by the inflexion -(e)s pronounced as [z], [s], [iz].
[z] dogs, days
-(е)s [s] hats, roofs
[iz] classes, roses, benches, bridges, dishes, garages
This is a productive way of forming the plural of nouns in Modern English. However, certain nouns form the plural in different ways, which cannot be regarded as productive. These are survivals of earlier formations. Here belong the following:
(1) Vowel change in the root of a word: man-men, woman-women, foot-feet, tooth-teeth, goose-geese, mouse-mice. (2) Suffix -en: ox-oxen.
(3) Vowel change + suffix –ren: child-children, brother-brethren (the latter is archaic and occurs only in high poetry and religious prose).
(4) Consonant change + suffix -(e)s:
house-houses [s — ziz]
bath —baths But:
m outh - mouths [θ - ðz] truth - truths
path - paths youth - youths [θ - θs, ðz]
c alf - calves But:
h alf – calves [f - vz] hoof – hoofs, hooves
knife – knives scarf – scarfs, scarves [f - fs, vs]
leaf - leaves Exceptions (no change in root sounds):
life — lives
loaf - loaves chief - chiefs
shelf - shelves [f - vz] death- deaths
thief - thieves month-r- months
wife - wives roof - roofs
wolf — wolves
(5) Homonymous forms for the singular and, the plural: deer — deer, sheep — sheep, swine — swine. (6) Some words borrowed from Greek or Latin retain their original plural forms.
Greek Loan-Words Singular Plural basis [‘beisis] bases ['beisi:z]
crisis [‘kraisis] crises [kraisi:z]
analysis [a'næləsis] analyses [a'næləsi:z]
thesis [‘θi:sis] theses [θi:si:z]
criterion [krai'tiəriən] criteria [krai'tiəriə]
phenomenon [fi'nominən] phenomena [fi'nominə]
Latin Loan-Words Singular Singular Plural datum [deitəm] data ['deitə]
formula [‘fo:mjulə] formulae [fo:mjuli:]
medium ['mi:djəm] media [mi:djə]
memorandum [,memə'rændəm] memoranda [,memə'rændə]
series [‘siəri:z] series [‘siəri:z]
These forms tend to be used in the language of science. In fiction and colloquial English the regular English plural form in -(e)s is generally used.
Thus in some cases two plural forms co-exist: antennae, antennas; formulae, formulas; memoranda, memorandums.