Nouns are a diverse group of words, and they are very common in English. Nouns are a category of words defining things—the name of people (Dr. Sanders, lawyers), places (Kansas, factory, home), things (scissors, sheet music, book), or ideas (love, truth, beauty, intelligence).

There are a lot of different categories of nouns, but before we get in too deep, let’s talk about pluralization.

Pluralization

A plural noun indicates that there is more than one of that noun (while a singular noun indicates that there is just one of the noun). Most plural forms are created by simply adding an -s or –es to the end of the singular word. For example, there’s one dog (singular), but three dogs (plural). However, English has both regular and irregular plural nouns. Regular plurals follow this rule (and other similar rules), but irregular plurals are, well, not regular and don’t follow a “standard” rule.

Regular Plurals

Let’s start with regular plurals: regular plural nouns use established patterns to indicate there is more than one of a thing. As was mentioned earlier, we add the plural suffix –s to most words (cats, bears, zebras). However, after sounds s, z, sh, ch, and j, we add the plural suffix –es (classes, sashes, foxes). Some words that end in z also double their ending consonant, like quizzes.

We also add the plural suffix –es to most words that end in o (potatoes, heroes, mosquitoes). However, when the words have a foreign origin (e.g.,Latin, Greek, Spanish), we  just add the plural suffix –s (tacos, avocados, maestros).

When a word ends in y and there is a consonant before y, we change the y to i and add –es. Thus sky becomes skies. When a word ends in –f or –fe, we change the f to v and add –es. Thus calf becomes calves.

However, there are some exceptions to these rules:

• donkeys not donkeies; alloys not alloies.
  • If the y follows another vowel, you simply add an –s.
• cliffs not clivves; chiefs not chieves
  • If there are two terminal fs, you simply add an –s.
  • If you still pronounce the f in the plural, then the spelling should retain the f as well.

Irregular Plurals

Irregular plurals, unlike regular plurals, don’t necessarily follow any particular pattern—instead, they follow a lot of different patterns. Because of this, irregular plurals require a lot of memorization; you need to remember which nouns belong to which type of pluralization. Mastering irregulars uses a different region of your brain than regular pluralization: it’s an entirely different skill set than regular pluralization. So don’t get too frustrated if you can’t remember the correct plural. If you’re ever in doubt, the dictionary is there for you.

The first kind of irregular plural we’ll talk about is the no-change or base plural. In these words, the singular noun has the exact same form as the plural (sheep, fish, deer, moose). Most no-change plurals are types of animals. The next type of irregular is the mid-word vowel change:

And last we have plural –en. In these words –en is used as the plural ending instead of –s or -es.

• child → children
• ox → oxen
• brother → brethren
• sister → sistren

The last category of irregular plurals is borrowed words. These words are native to other languages (e.g., Latin, Greek) and have retained the pluralization rules from their original tongue.

Singular –us; Plural –i

• cactus → cacti
• fungus → fungi
• syllabus → syllabi

In informal speech, cactuses and funguses are acceptable. Octopuses is preferred to octopi, but octopi is an accepted word.

Singular -a; Plural –ae

• formula → formulae (sometimes formulas)
• vertebra → vertebrae
• larva → larvae

Singular –ix, –ex; Plural –ices, –es

• appendix → appendices (sometimes appendixes)
• index → indices

Singular –on, –um; Plural –a

• criterion → criteria
• bacterium → bacteria
• medium → media

Singular –is; Plural –es

• analysis → analyses
• crisis → crises
• thesis → theses