Making Plurals and Third Person Verbs: When to Add -S vs -ES

The S vs ES Decision

When do you add just '-s' and when do you add '-es' to make plurals or third person verbs? Many learners guess, but there are clear rules that govern this choice.

The Basic Rules:

• Add -S to most words
• Add -ES when the word "hisses" or changes form

Let's break this down systematically.

Rule 1: Add -S to Most Words

The default is to add just '-s' for both plurals and third person singular verbs.

Regular Plurals

Third Person Singular Verbs

Rule 2: Add -ES When Words "Hiss"

The Hissing Rule: Add '-es' when the base word ends in sounds that "hiss" or are hard to pronounce with just '-s'.

Words Ending in S, SS, X, Z, ZZ

These already make hissing sounds, so adding just '-s' would be impossible to pronounce clearly.

Words Ending in SH, CH

Rule 3: Words Ending in O

Most words ending in 'o' add '-es', but there are important exceptions.

Add -ES (Most Common)

Add -S (Exceptions)

Memory tip: Musical instruments and shortened words usually take just '-s'.

Rule 4: Words Ending in Consonant + Y

The Rule: Change 'y' to 'i' and add '-es'.

But: If there's a vowel before 'y', just add '-s':

• boys (not boies)
• plays (not plaies)
• keys (not keies)

Rule 5: Words Ending in F or FE

The Rule: Change 'f' or 'fe' to 'v' and add '-es'.

Exceptions that just add -S:

• roofs (not rooves)
• chiefs (not chieves)
• beliefs (not believes)

Pronunciation Patterns

The -S Ending Sounds

The '-s' ending has three different pronunciations:

1. /s/ sound - after voiceless consonants:

• cats /kæts/
• books /bʊks/
• helps /hɛlps/

2. /z/ sound - after voiced consonants and vowels:

• dogs /dɔgz/
• cars /kɑrz/
• plays /pleɪz/

3. /əz/ sound - when adding '-es':

• glasses /glæsəz/
• watches /wɑtʃəz/
• buzzes /bʌzəz/

Quick Decision Chart

Ask yourself:

1. Does it hiss? (s, ss, x, z, sh, ch) → Add -ES
2. Does it end in consonant + Y? → Change Y to I, add -ES
3. Does it end in F/FE? → Usually change to V, add -ES
4. Does it end in O? → Usually add -ES (exceptions: photos, pianos)
5. Everything else? → Add -S

Common Mistakes for Spanish Speakers

1. Forgetting the extra syllable: glasses is /glæsəz/ (2 syllables), not /glæss/
2. Y to I changes: babies not babys
3. F to V changes: knives not knifes
4. Pronunciation: The '-s' changes sound based on the previous letter

Practice Exercise

Make these words plural or third person singular:

1. church → ?
2. boy → ?
3. city → ?
4. roof → ?
5. potato → ?
6. photo → ?

Answers:

1. churches (ch = hissing sound, add -es)
2. boys (vowel + y, just add -s)
3. cities (consonant + y, change to i + es)
4. roofs (exception, just add -s)
5. potatoes (o ending, add -es)
6. photos (exception, just add -s)

Memory Device

"When English Hisses, Add -ES"

• Snakes hiss → glasses
• SHells hiss → dishes
• CHildren hiss → watches
• X marks hiss → boxes
• Zebras hiss → buzzes

For everything else, start with '-s' and apply the special rules for Y, F, and O endings.

These rules eliminate guesswork and give you a systematic approach to one of English's most common grammar patterns.

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