Countable vs. Uncountable Nouns

Countable nouns are usually concrete nouns and they can be counted, e.g. a table, three tables.

Uncountable nouns cannot be counted.

We normally do not add ‘a/an’ to them and do not make them plural.

They denote

1) substances

– materials

wood, wool, paper

– liquids

water, tea

– some food items

butter, meat

– chemicals, gases

calcium, oxygen

2) abstract nouns:

love, peace, generosity, time

3) activities, sports:

jogging, studying, football

4) collective nouns:

furniture, luggage, equipment, accommodation (countable in US English!), traffic, jewellery

5) names of subjects:

Mathematics, Geography

6) languages

French, Russian

7) other

advice*, behaviour, chaos, damage, evidence, hair*, information, money*, news*, luggage, luck, work, progress, pollution, research*, scenery, weather, fruit*, permission

*in contrast to the correspoding nouns in Russian

Singular vs. Plural Nouns

Most plural nouns are built by adding -s / -es to the singular.

cup – cups (pronounced as [s] after voiceless consonants)
wave – waves, toe – toes (pronounced as [z] after voiced consonants and vowels)

rose – roses (pronounced as [iz] after sibilants)

Special rules

1) -s, -sh, -ch, -x, -z + -es.

loss – losses, bench – benches, bush – bushes, box – boxes, buzz – buzzes

2)  -o + -es

echo – echoes, hero – heroes, potato – potatoes, mosquito – mosquitoes, volcano – volcanoes

But !

vowel + o + -s

cuckoo – cuckoos

radio – radios

+ other nouns (of foreign origin)

o+s

bravo, casino, kilo, photo, piano, solo, zero, etc.

3) consonant + y

y -> i + es 

sky – skies
country – countries
But !

Vowel + y + -s
day – days

Note!
Most proper names ending in -y take the plural in -s.

Mary – Marys
Rowley – Rowleys

4) In some nouns ending in -f or -fe

-f→ -v + -es

calf – calves

elf – elves

half – halves

knife – knives

leaf – leaves

life – lives

loaf – loaves

self – selves

shelf – shelves

thief – thieves

wife – wives

wolf – wolves

But !

The following nouns in -f or -fe take only -s

belief – beliefs

cliff – cliffs

grief – griefs

gulf – gulfs

proof – proofs

safe – safes

5) Some nouns form their plural in -en.

an ox – oxen

a child – children

6) A few nouns form their plural by a change of vowel.

a man – men (also firemen, salesmen etc.)
a woman – women
a foot – feet
a tooth – teeth
a goose – geese
a mouse – mice

a person – people

7) Some nouns have the same form in both singular and plural:
deer, fish, sheep, salmon, swine, trout.

8) Some noun borrowed from from other languages have special plural forms.

– from Latin:

-um → -a

bacterium – bacteria

datum – data

-us → – i

alumnus [ə’lʌmnəs]– alumni [ə’lʌmnaɪ]

stimulus – stimuli

other Latin nouns:

series – series

species – species

– from Greek:

-is → es

analysis – analyses

axis – axes

basis – bases

diagnosis – diagnoses

hypothesis – hypotheses

oasis – oases

synopsis – synopses

thesis – theses

-on → a

phenomenon – phenomena

criterion – criteria

! Some nouns have the new English plural along with the original foreign one:

appendix – appendices/appendixes

curriculum – curriculums/curricula,

formula – formulas/formulae,

memorandum – memorandums/memoranda

9) Plural compound nouns normally take -s in the last pat;

spoonful – spoonfuls

stepson – stepsons
forget-me-not – forget-me-nots

merry-go-round – merry-go-rounds

Sometimes -s is added to the first part.
editor-in-chief – editors-in-chief
maid-of-honor – maids-of-honor (‘the main bridesmaid at a wedding’)
son-in-law – sons-in-law

10) Nouns used only in the plural form (pluralia tantum)

– clothing (clothes, dungarees, jeans, pyjamas, shorts, trousers, trunks)

– tools/equipment (scissors, glasses/spectacles, scales, handcuffs, pliers)

– games (dominoes, darts, cards)

– other (contents, goods, remains, savings, stairs, thanks, troops, whereabouts)