Irregular plurals · Grade 1
Most nouns make their plural with -s or -es, but some don't follow the rules. These irregular plurals change their vowel, add a different ending, change f to v or stay exactly the same. You learn them by heart, and saying them out loud helps.
Key facts
- Some nouns change their vowel: man → men, woman → women, foot → feet, tooth → teeth, goose → geese, mouse → mice.
- A few add -en or -ren: child → children, ox → oxen. And person → people.
- Some stay the same: one sheep, two sheep; also deer, fish and aircraft.
- Many nouns ending in f or fe change to -ves: knife → knives, leaf → leaves, half → halves. But some just add -s: roof → roofs, chef → chefs, cliff → cliffs.
- Some words from Latin and Greek keep their own plurals: cactus → cacti, crisis → crises, phenomenon → phenomena, criterion → criteria.
Worked examples
Example 1
Write the plural: one child, three ___
Answer: children
Example 2
Write the plural of knife.
Answer: knives
Example 3
Choose: The farmer has twenty (sheep / sheeps).
Answer: sheep
Example 4
Correct the mistake: My foots are wet.
Answer: My feet are wet.