What are the rules when changing the singular form of a noun into the plural form?

Answer 1

For most regular nouns, the way to make them plural is to add an -s. For example: book is singular (one book); books is plural (more than one). Girl is singular. Girls is the plural. Computer is singular; the plural is computers.

But English has many exceptions. If a noun has one syllable and ends in Y, the plural is regular: day/days. Toy/toys. But if there are two or more syllables and the noun ends in the letter Y, you form the plural by dropping the Y and turning the ending into -ies. For example: baby is singular; babies is plural. Country is singular. Countries is plural. If a noun already ends in an s, you often add an -es to form the plural: boss/ bosses. Kiss/kisses. And if a noun ends in the letter X, you usually add an -es to form the plural. For example: box becomes boxes; fox becomes foxes. BUT, as you will see next, there are exceptions. One of them is ox (an animal)-- its plural is oxen.

Some nouns are not regular (ox is one example). These irregular nouns have a unique plural: for example, words that come from foreign languages have an irregular plural: medium comes from Latin, and its plural is media. Datum also comes from Latin, and its plural is data. The same for stimulus (singular)-- the plural is stimuli.

Some other irregular plural nouns: Child is singular, but the plural is children. Woman has an irregular plural: women. Man becomes men. Foot becomes feet. The plural of mouse is mice. And the plural of tooth is teeth. There are also some non-countable nouns with no plural at all, such as news, research, and information. So, the short answer is most nouns are regular and just use an -s to become plural. But all you can do is find a good dictionary (or a good web-page about English grammar) so you can memorize the irregular nouns.

Answer 2

The rules for changing a singular noun into a plural form generally involve adding an "s" or "es" to the end of the noun. However, there are irregular nouns that change in different ways when forming the plural, such as changing a "y" to "i" and adding "es" or changing the word entirely, like "man" to "men." It's important to learn the specific rules for irregular plurals in English.