Nouns with Special Plural Forms
The plural forms of most nouns are made by adding -s or -es. But some nouns are not made plural by adding -s or -es. These nouns have irregular plural forms.
For some of these nouns, the singular and plural forms are spelled differently. For others, the singular and plural forms are the same.
The following are examples of nouns that have different singular and plural forms:
child—childrenox—oxen
foot—feet
man—men
mouse—mice
woman—women
goose—geese
tooth—teeth
The following are examples of nouns that have the same singular and plural forms:
series—series
moose—moose
traffic—traffic
deer—deer
salmon—salmon
trout—trout
wheat—wheat