The most common ending is "-s":
* Singular: cat, dog, tree, book, chair
* Plural: cats, dogs, trees, books, chairs
If the singular word ends in "-s", "-x", "-ch", "-sh" or "-z", we add "-es":
* Singular: bus, box, church, dish, buzz
* Plural: buses, boxes, churches, dishes, buzzes
If the singular word ends in a consonant followed by "-y", we change the "-y" to "-ies":
* Singular: baby, city, story, fly
* Plural: babies, cities, stories, flies
Exceptions:
* Some words have irregular plural forms, like "child" (children), "person" (people), and "mouse" (mice).
* Some words borrowed from other languages keep their original plural forms, like "octopus" (octopuses/octopodes), "cactus" (cacti/cactuses) and "phenomenon" (phenomena).
Beyond the Basics:
* Compound nouns: The plural usually goes on the main noun: "toothbrushes", "newspapers", "mother-in-laws".
* Proper nouns: Some proper nouns are treated as singular (like "London"), while others have regular plurals ("the Joneses").
* Uncountable nouns: Nouns like "water", "air", "information" have no plural form.
Let me know if you'd like more examples or have any other questions about English plural endings.