The Irregular Plurals (from Khan Academy)

The Irregular Plurals

(from Khan Academy)

Irregular plural nouns take several forms

• Nouns ending in -f and -fe

• Nouns ending in -o

• Nouns That Change Vowels

• Nouns That Change Substantially

• Nouns That Do Not Change At All

Irregular plural nouns take several forms

• Plurals of Latin and Greek words

• Nouns ending in -us

• Nouns ending in -is

• Nouns ending in -om

• Nouns ending in -um

• Nouns ending in -ix

Nouns ending in -f and -fe

• Think of a couple of nouns that end in either -f or -fe.

• Get ready to share...

Open Ended

What NOUNS ending in -F of-FE did you come up with?

Open Ended

What are the PLURAL FORMS of those NOUNS ending in -F of-FE?

Some NOUNS ending in -f or -fe include...

• knife, life, wife, calf, and leaf

• knive becomes knives

• life becomes lives

• wife becomes wives

• calf becomes calves

• and leaf becomes leaves

Nouns ending in -o

• Think of a couple of nouns that end in -o.

• Get ready to share...

Open Ended

What NOUNS ending in -o did you come up with?

Open Ended

What are the PLURAL FORMS of those NOUNS ending in -o

Some NOUNS ending in -o include...

• potato, tomato, hero, torpedo, and veto

• potato becomes potatoes

• tomato becomes tomatoes

• torpedo becomes torpedoes

• veto becomes vetoes

Some NOUNS change vowels

• What are the plurals of the following nouns?

• foot, tooth, goose, man, and woman

• get ready to share...

Open Ended

What are the plurals of the following nouns?

foot, tooth, goose, man, woman

These NOUNS that change vowels take the following plural forms...

• foot becomes feet

• tooth becomes teeth

• goose becomes geese

• man becomes men

• woman becomes women

Some NOUNS change substantially

• What are the plurals of the following nouns?

• louse, mouse, die, ox, child, and person

• Get ready to share...

Open Ended

What are the plurals of the following nouns?

louse, mouse, die, ox, child, person

These NOUNS that change substantially take the following plural forms...

• louse becomes lice

• mouse becomes mice

• die becomes dice

• ox becomes oxen

• child becomes children

• person becomes people

Some NOUNS do not change at all

• What are the plurals of the following nouns?

• sheep, fish, deer, moose, swine, buffalo, shrimp, and trout

• Get ready to share...

Open Ended

What are the plurals of the following nouns?

sheep, fish, deer, moose, swine, buffalo, shrimp, trout

That's right! These plural NOUNS stay the same:

• one sheep, two sheep

• one fish, two fish

• one deer, two deer

• one moose, two moose

• one swine, two swine

• one buffalo, two buffalo

That's right! These plural NOUNS stay the same:

• one shrimp, two shrimp

• one trount, two trount

• and one bison, a billion bison

Poll

What do you think is the plural form of the word "focus"?

• focus

• focuses

• focusen

• foci

The answer is....FOCI!

One focus becomes three foci

Latin or Greek words

There are certain words we use on a regular basis, especially in mathematical and scientific contexts, that are borrowed from Latin or Greek. Many of these words retain their Latin or Greek plurals in math and science settings. Some of them also have anglicized plural forms that have come into common use.

Poll

What do you think is the plural form of the word "radius"?

• radius

• radiuses

• radiusen

• radii

The answer is....RADII!

One radius becomes four radii

Multiple Choice

What do you think is the plural form of the word "fungus"?

• fungus

• fungi

• fungusen

• funguses

To make a word ending in -us plural, change -us to -i. Many plurals of words ending in -us have anglicized versions, formed by simply adding -es. The latter method sounds more natural in informal settings. If there is an anglicized version that is well accepted, this will be noted in the dictionary.

Multiple Choice

What do you think is the plural form of the word "cactus"?

• cacti

• cactus

• cactusar

• cactuses

To make a word ending in -us plural, change -us to -i. Many plurals of words ending in -us have anglicized versions, formed by simply adding -es. The latter method sounds more natural in informal settings. If there is an anglicized version that is well accepted, this will be noted in the dictionary.

Multiple Choice

What do you think is the plural form of the word "octopus"?

• octopusen

• octopusi

• octopuses

• octopi

Multiple Select

What do you think is the plural form of the word "hippopotamus"?

• hippopotamus

• hippopotami

• hippopotopatomupopes

• hippos

Some NOUNS ending in -is are odd

• What are the PLURAL forms of the following:

• axis, analysis, crisis, thesis

• Get ready to share...

Open Ended

What do you think are the plural forms of axis, analysis, crisis, thesis?

Multiple Choice

Try choosing from the following:

• two axis, two analysis, two crisis, two thesis

• two axises, two analysises, two crisises, two thesises

• two axes, two analyses, two crises, two theses

Nouns with an -is ending can be made plural by changing -is to -es. Some people have a hard time remembering that the plural of crisis is crises and the plural of axis is axes, but crisises and axises are incorrect.

Some NOUNS ending in -on are unusual

• What are the PLURAL forms of the following:

• phenomenon and criterion

• Get ready to share...

Open Ended

What do you think are the plural forms of criterion and phenomenon?

Greek words inding in -on change their ending to -a.

Thus, one criterion becomes two criteria.

And one phenomenon becomes two phenomena.

Multiple Select

What do you think are the plural forms of criterion and phenomenon?

• one criterion, two criteria

• one phenomenon, two phenomena

• one criterion, two criterius

• one phenomenon, two phenomenus