Irregular Noun Plurals

When the final -y is preceded by a consonant, change the -y to -i and add -es:


baby–>babies
lady–>ladies


If a noun ends in -fe or -f, the ending is changed to -ves (except: beliefs, chiefs, roofs, staffs).


life–>lives
thief–>thieves


Add -es to nouns ending in -sh, -ch, -s, -z, and -x. (Exceptions: monarchs, stomachs.)


wish–>wishes
class–>classes


Both the -s and -es spellings are accepted for nouns ending in -o.

tomato–>tomatoes
hero–>heroes


The plural form of these nouns is also irregular.

child–>children
foot–>feet
goose–>geese
man–>men
tooth–>teeth

The plural is the same as the singular for these nouns.

deer–>deer
fish–>fish
sheep–>sheep
species–>species


The final sound of these plurals is pronounced like the word sees.


crisis–>crises
thesis–>theses