The vast majority of nouns in the English language are made plural by adding an "s" or "es" to the end of the word. For example, book, apple, house, table, door, cat, bush, boss are just some of the millions of words that become plural with the simple addition of an "s" (books, apples, houses, tables, doors, cats, bushes, bosses). However, certain nouns have "irregular" plurals which do not behave in this standard way.
For most nouns, the general rule for making the word plural is:
Box + es = boxes
catch + es = catches
Dish + es = dishes
Candy = candies
Dog = dogs
Kid = kids
Certain words do not follow the above rules for regular plurals. There are some common types of irregular plurals that occur, and some words simply have no plural form at all.
While it is useful to memorize the common irregular plurals, for many words you simply have to know and understand that it is an irregular plural as a result of speaking and hearing English.
If you are talking about multiple varieties or types of these irregular plurals, you cannot make them plural by adding an "s" or "es" to the end. Instead, you need to make them plural by adding a descriptive phrase. For example:
Certain other nouns have the same plural form as singular form. A large number of animals happen to follow this rule. For example, among others:
In addition to non-count nouns and unchanging nouns, there are several different types of irregular plurals which follow a pattern in the English language.
Knife = knives
Wife = wives
Half = halves
Loaf = loaves
Syllabus = syallabi
Tomato = tomatoes
Certain words do not add a letter to the end, but instead change the word itself. These words simply need to be memorized. Some examples include:
The best way to learn and understand irregular plurals is to practice speaking the English language, to read a great deal, to pay attention to words and phrases that you see and hear and to assemble a list of words with irregular plurals so you can begin to understand how to make each noun plural correctly.