How to use S or ES Learn the Rules for Making Words Simply

Introduction

Have you ever hesitated before adding an ending to a word to make it plural? You’re not alone. English grammar has its fair share of quirks, and forming plurals is one of them. While adding “s” or “es” may seem easy at first glance, understanding when and why to use each is key to avoiding common mistakes.

In this complete guide, you’ll learn when to add “s”, when to use “es”, and how to handle irregular plurals and exceptions with confidence.

Rule 1: The Basic “S” Rule

For most English nouns, form the plural by simply adding “s.”

Examples:

• Book → books
• Cat → cats
• Apple → apples

This is the default rule and covers the majority of English words.

Rule 2: The “ES” Rule – When Pronunciation Requires It

If a noun ends in a hissing or sibilant sound, adding just “s” makes it hard to pronounce. To fix this, we add “es.”

Add “es” to nouns ending in:

• -s (Bus → buses)
• -ss (kiss → kisses)
• -sh (Dish → dishes)
• -ch (Watch → watches)
• -x (Box → boxes)
• -z (Quiz → quizzes)

✅ According to Oxford English Grammar, this rule helps avoid awkward consonant clusters and improves pronunciation.

Rule 3: Words Ending in “Y” – Consonant or Vowel?

• If a consonant comes before the “y,” change the “y” to “i” and add “es.”

• Baby → babies
• City → cities

• If a vowel comes before the “y,” just add “s.”

• Boy → boys
• Key → keys

Tip: Listen to the letter before “y.” If it’s a vowel (a, e, i, o, u), the rule is simpler!

Rule 4: Words Ending in “O” – The Tricky Ones

There is no universal rule for these words, but a helpful pattern is:

• Traditional English words usually take “es.”

• Potato → potatoes
• Hero → heroes

• Imported or shortened words usually take just “s.”

• Photo → photos
• Piano → pianos

✅ Source: Merriam-Webster Dictionary

Rule 5: Words Ending in “F” or “FE” – Change or Don’t Change?

• For many words, change “f” to “v” and add “es.”

• Leaf → leaves
• Knife → knives

• But some words just take an “s.”

• Roof → roofs
• Belief → beliefs

📌 These exceptions are best memorized. Most common ones follow the “v” change rule.

Irregular Plurals – Beyond S or ES

Some nouns have irregular plurals that don’t follow typical rules:

hese need to be memorized, but they’re frequently used in English.

Invariable Nouns – No Change in Plural Form

Some nouns stay the same whether singular or plural:

• Sheep
• Deer
• Species
• Aircraft

🧠 Context is key! These words require no “s” or “es.”

Compound Nouns – Where Does the “S” Go?

Hyphenated or spaced compounds: pluralize the main noun.

• Sister-in-law → sisters-in-law
• Runner-up → runners-up

Closed compounds: add “s” at the end.

• Greenhouse → greenhouses
• Toothbrush → toothbrushes

Common Mistakes to Avoid

❌ Apostrophe Errors

• Wrong: I bought three apple’s.
• Right: I bought three apples.

Apostrophes show possession, not plurality (except for clarity in symbols like A’s or 7’s).

Quick Practice

Turn these singular nouns into plurals:

1. Dish → dishes
2. Story → stories
3. Wolf → wolves
4. Radio → radios

More practice builds confidence!

Conclusion: S or ES?

By mastering these pluralization patterns:

• You’ll write with greater accuracy.
• Avoid common ESL spelling mistakes.
• Build confidence in both speaking and writing.

Even native speakers occasionally trip up—so don’t worry if you need a refresher. Use this guide whenever in doubt!

FAQs: S or ES? Learn the Rules for Making Words