Irregular Plural Nouns worksheet for students to practice converting singular nouns to their plural forms.

Let’s go through each word one by one and figure out its plural form. Some of these are tricky because they don’t just add “-s” or “-es” — that’s why they’re called *irregular*!

1. ox → This is an old word. The plural is oxen.
2. dwarf → You might think “dwarfs,” but the traditional plural is dwarves (like in fairy tales).
3. fungus → Comes from Latin. Plural is fungi.
4. focus → Also Latin. Plural is foci (pronounced FOE-sigh) — though sometimes people say “focuses,” we’ll use the irregular one here.
5. quiz → Just add “-zes” → quizzes.
6. thief → Change “f” to “v” and add “-es” → thieves.
7. wife → Same rule: change “f” to “v” and add “-es” → wives.
8. tuna → Fish like this often stay the same → tuna (or tunas, but tuna is accepted as plural too).
9. trout → Another fish that doesn’t change → trout.
10. moose → Doesn’t change at all → moose.
11. wharf → Can be wharves (changing f to v + es) — that’s the irregular version.
12. thesis → From Greek. Plural is theses (THEE-seez).
13. man → Very common irregular → men.
14. goose → Changes completely → geese.
15. salmon → Fish again — usually stays the same → salmon.
16. shrimp → Usually unchanged → shrimp (though “shrimps” exists, we’ll go with the more common irregular form).
17. self → Change “f” to “v” and add “-es” → selves.
18. larva → From Latin. Plural is larvae (LAR-vee).

Now let’s double-check a few that could be confusing:

- “Dwarf” → dwarves ✔ (not dwarfs for this worksheet)
- “Focus” → foci ✔ (standard academic plural)
- “Thesis” → theses ✔
- “Man” → men ✔
- “Goose” → geese ✔
- “Self” → selves ✔
- “Larva” → larvae ✔

All look good!

Final Answer:
1. oxen
2. dwarves
3. fungi
4. foci
5. quizzes
6. thieves
7. wives
8. tuna
9. trout
10. moose
11. wharves
12. theses
13. men
14. geese
15. salmon
16. shrimp
17. selves
18. larvae