Some nouns change letters when switching from singular to plural form. Here is a list of words that change their spelling when becoming plural:
child becomes children
man becomes men
woman becomes women
foot becomes feet
tooth becomes teeth
Other nouns use the exact same word for the singular and the plural form. Here is a list of words that do not change when becoming plural:
bison – I saw one bison. I saw many bison.
deer – A deer was in our yard. I counted six deer in our yard.
fish – I caught a fish. My cousin has ten fish in her tank.
moose – We saw a moose while driving in Montana. There were several moose along the road.
sheep – Mary took her favorite sheep to the fair. My uncle raises many sheep.
The unusual plural nouns need to be memorized so that you are ready to write them correctly.
▶Now you try it. Write the plural form of each of these unusual nouns: tooth, fish, child, foot. How did you do? Have you got those unusual plurals memorized? Good for you!