Some words do not follow the regular rule of adding “s” or "es" to form plurals and are called “irregular plurals”. Some words may stay the same for the plurals, some may change completely, and others may add endings other than “s” or "es". These are words that you must memorize.
1. The following are examples of words that stay the same for both singular and plural forms
Milk: I need to buy a lot of milk. I need to buy one gallon of milk.
Bread: That bread looks good. Where is all the bread?
Cheese: John wants a piece of cheese. Look at all that cheese!
Toast: I made one piece of toast. John wants three pieces of toast.
Deer: The deer is in the woods. The deer are in the woods.
Sheep: I saw one sheep at the zoo. The sheep are running.
Jewelry: She only has one piece of jewelry. Mary has lots of jewelry.
grass: Let's sit on the grass. All that grass is so long!
golf: I enjoy playing golf. Yesterday I played five rounds of golf.
series: What is that TV series called? Those TV series are great.
salmon: All salmon are powerful swimmers. That one salmon is brightly colored.
2. The following are examples of nouns used in counting that stay the same
Hundred stays the same: There are one hundred people in the crowd. There are two hundred people in the crowd.
Thousand stays the same: Do you have a thousand dollars? Do you have ten thousand dollars?
Million stays the same: I saw one million pennies. I saw five million pennies.
Billion stays the same: My son has a billion legos. My son has three billion legos.
3. The following are examples of nouns that change to form plurals
Goose changes to geese: One goose is swimming. Five geese are swimming.
Mouse changes to mice: Did you see that mouse? Did you see those mice?
Person changes to people: I know that person. I know those people.
Foot changes to feet: My foot hurts. My feet hurt.
Man changes to men: I see an old man. I see five old men.
Woman changes to women: One woman has long hair. Those two women have short hair.
Medium changes to media: Radio is a good medium. I am not familiar with all media.
Child changes to children: The child over there is crying. All of those children are crying.
Tooth changes to teeth: The child lost a tooth. My children have lost teeth.
4. The following are examples of words that end in /f/. To form the plural, drop the /f/ add “ves”.
Calf changes to calves: I see one calf. I see two calves.
Thief changes to thieves: The thief was caught. The thieves were caught.
Wife changes to wives: His wife is beautiful. Their wives are beautiful.
Wolf changes to wolves: I don't like that wolf. I don't like those wolves.
Half changes to halves: Could I have half a cookie? Could I have five cookies?
Knife changes to knives: That knife is sharp. Those knives are sharp.
Leaf changes to leaves: I stepped on a leaf. I stepped on five leaves.
Life changes to lives: My life is complete. Our lives are complete.
Loaf changes to loaves: I have a loaf of bread. I have two loaves of bread.
Self changes to selves: I can do it by myself. They can do it by themselves.
Shelf changes to shelves: The shelf broke. The two shelves broke.
5. The following are examples of plural nouns that have no singular form
Arms (which refers to weapons): The soldier carries arms at all times.
Contents: Mary showed me the contents of those boxes.
Belongings: Her belongings are in her room.
Clothes: My clothes are all clean.
Congratulations: Congratulations on your victory!
Remains: The police found the remains of the victim in the woods.
Earnings: John's earnings exceeded one million dollars.
Goods: We have the goods here for you.
Outskirts: My house is on the outskirts of the city.
Surroundings: I know my surroundings very well.
Thanks: Thanks so much for the gift.
Troops: The troops are finally coming home.
Trousers: I bought new trousers last week.
Pants: Women like to wear pants.
Mathematics: Mathematics is my favorite subject.
Means: I have the means to do it, but not the time.