Rules of pluralization

1#: Some nouns ending with a consonant are made plural by adding -s at the end.
2#: Some others by adding -es at the end.
3#: Nouns ending in y with a consonant before the y, are made plural by replacing the y by an i and adding -es.
4#: Nouns ending in y with a vowel before the y, are made plural by adding -s.
5#: If a noun ends in -f, you often change f to v, and add -es to make it plural.
6#: With some words that end in -fe, you change f to v, and add -s to make it plural.
7#: If a noun ends in -o, you just add -s to form the plural, but with some nouns, that end in o-, you add -es to form the plural.
8#: Some plural nouns don't follow the -s rule. They don't end in -s, -es, -ies, or -ves. Instead, the word changes form. E.g.: Mouse = mice, in plural form.
9#: Some nouns are always plural, and some nouns are the same as the singular noun.