What are the 30 rules in forming plural nouns?

Answer 1

A plural noun is a word for two or more people, places, or things. Here are some rules to make singular nouns into plural nouns:

• To make most nouns plural, add an s or es to the end of the word. These are called regular plurals (or regular nouns). Example: the plural of neighbor is neighbors, the plural of flower is flowers.
• Nouns ending in s, z, ch, sh, or x, add es to the end of the word to make it plural. The plural of dish is dishes.
• Some nouns ending with o are pluralized by adding and es to the end of the word. The plural of tomato is tomatoes.
• Most nouns ending with o are pluralized by adding s to the end of the word. The plural of photo is photos.
• Nouns that form their plural in some other way are called irregular plural (or irregular nouns). Example: the plural of child is children, the plural of foot is feet.
• When a noun ends in a y, change the y at the end of the word to an ies. The plural of berry is berries.
• Some nouns ending with y, preceded by a vowel, are pluralized by just adding s to the end of the word. The plural of day is days.
• Nouns ending with f or fe, change to f or the fe to ves to form the plural. The plural of life is lives.
• Nouns ending with ff are usually pluralized by just adding an s to the end of the word. The plural of cuff is cuffs.
• Some nouns change the vowel sound to become plural. The plural of man is men, the plural of tooth is teeth.
• Some Old English plurals are still in use. The plural of child is children, the plural of ox is oxen.
• Some nouns that end with is, the ending is changed to es to form the plural. The plural of crisis is crises.
• Some nouns that end with um, the um is replaced with an a. The plural for datum is data, the plural for medium is media.
• Some nouns that end with on, the on is replaced with an a. The plural of phenomenon is phenomena.
• Some nouns that end is a, change the a at the end of the word to ae. The plural of larva is larvae.
• Some nouns that end in ex or ix, the plural is formed by changing the x to ces. The plural of index is indeces, the plural of matrix is matrices.
• Some nouns that end in us, the plural is formed by changing the us to i. The plural of cactus is cacti, the plural of radius is radii.
• Nouns ending in eau, the plural is formed by adding x to the end of the word. The plural of bureau is bureaux.
• There are any number of other variations such as the plural of tempo is tempi; the plural of cherub is cherubim; the plural of person is people. But language evolves over time or we would still be speaking like Shakespeare.
• Even as I type these rules, some are officially amended. For example, the plural forms indeces and indexes are both being accepted as correct plurals for index and the plural forms; bureaux and bureaus are both being accepted as correct plurals for bureau, as are many other irregular plurals being found in standard dictionaries with modernized plural options.

Answer 2

There are no specific "30 rules" for forming plural nouns in English. Plural nouns are generally formed by adding "-s" to the end of the singular form, but there are exceptions like changing the spelling (e.g., "man" to "men") or using irregular forms (e.g., "child" to "children"). It's best to learn plural formations through practice and exposure to the language.