Regular plurals: add -s

Most nouns simply add -s:

SingularPlural
catcats
bookbooks
dogdogs
teacherteachers
carcars

Spelling rules

RuleWhenExamples
add -esAfter -s, -sh, -ch, -x, -zbus → buses · box → boxes · watch → watches
change -y → -iesConsonant + ybaby → babies · city → cities · family → families
keep -ysVowel + yday → days · boy → boys · key → keys
add -esAfter -o (some words)potato → potatoes · tomato → tomatoes
change -f/-fe → -vesSome words ending in -f/-feleaf → leaves · knife → knives · wife → wives

Irregular plurals

These plurals must be memorised — they don't follow any pattern:

SingularPluralSpanish
manmenhombre → hombres
womanwomenmujer → mujeres
childchildrenniño → niños
personpeoplepersona → personas
toothteethdiente → dientes
footfeetpie → pies
mousemiceratón → ratones
fishfishpez/peces (same form)
sheepsheepoveja/ovejas (same form)
peoples vs people: people is already plural — never say "peoples" when talking about persons. "There are many people here." However, "peoples" (with -s) is used in formal/political contexts to mean "ethnic groups or nations" — a very different meaning.

Exercise

1. What is the plural of "child"?

2. What is the plural of "city"?

3. There are five ______ in the garden. (one woman → several)

4. What is the plural of "box"?

5. There are many ______ in the lake. (one fish → many)