Grade by Grade
B. Foundations of Language · Cursive, Spelling and Sentences

Suffixes: Meanings and Spelling Changes

B2.3About 40 minutes
Learning goals
  • I can find the base and the suffix in a word, and tell what the suffix means.
  • I can use new suffixes like -ment, -able, -y and -or to make and spell words.
  • I can make tricky plurals: berries, leaves, mice.
  • I can use the spelling changes: double, drop the e, and change y to i.

Words to know

morpheme
The smallest part of a word that has meaning. Help, -ful and un- are all morphemes.
base
The main part of a word that carries its meaning, like help in helpful.
suffix
A word part added to the end of a base, like -ment in enjoyment.
plural
A word that means more than one, like dogs or mice.
word sum
A way to show the parts of a word: help + ful = helpful.

Remember from Grade 2

In Grade 2 you added endings like -s, -ed, -ing, -er, -est and suffixes like -ful, -less, -ness and -ly. You learned three spelling changes:

  1. Double the last consonant: hop → hopping.
  2. Drop the e: bake → baking.
  3. Change y to i: cry → cried.

In Grade 3 you will learn more suffixes, think about what each one means, and spell tricky plurals.

Word parts carry meaning

Each part of a word is called a morpheme. When you know what the parts mean, you can read, spell and understand big words.

Look at enjoyment: enjoy + ment. -ment turns an action into a thing. Enjoyment is the feeling of enjoying something.

enjoymentenjoy + ment = enjoyment
A word sum: base + suffix
SuffixMeaningExamples
-mentthe act of, or the result ofenjoyment, payment, movement
-ablecan be, or able to bewashable, breakable, readable
-yfull of, or likesnowy, windy, rainy, sandy
-er / -ora person whoteacher, skater, actor, sailor
-fulfull ofhelpful, joyful, careful
-lesswithoutcareless, hopeless, endless
-nessthe state of beingkindness, sadness, darkness
-lyin a wayslowly, quickly, gently
Suffixes and what they mean

Spelling changes: which rule?

Before you add a suffix, look at the end of the base and the start of the suffix.

  • Suffixes that start with a vowel: -ing, -ed, -er, -est, -able, -y.
  • Suffixes that start with a consonant: -ment, -ful, -less, -ness, -ly, -s.
RuleWhenExamples
Just addMost wordshelp → helpful, wash → washable, enjoy → enjoyment
Double the last letterOne short vowel + one consonant, and a vowel suffixsun → sunny, fog → foggy, run → runner
Drop the eBase ends in silent e, and a vowel suffixshine → shiny, ice → icy, use → usable
Keep the eBase ends in silent e, and a consonant suffixhope → hopeful, safe → safely, move → movement
Change y to iConsonant + y, and any suffix except -inghappy → happiness, happily; busy → busily
Keep the yVowel + y (like ay, oy), or adding -ingplay → playful, enjoy → enjoyment, cry → crying
Spelling change rules
Worked example

Let's add -y to "sun"

sun + y = ?

  1. Does -y start with a vowel? Yes (here y works like a vowel).
  2. Does sun have one short vowel and end in one consonant? Yes: s-u-n.
  3. So double the n.
  4. sun + y = sunny

sunny

Worked example

Let's add -ness to "happy"

happy + ness = ?

  1. happy ends with consonant + y (p + y).
  2. We are not adding -ing, so change y to i.
  3. happi + ness = happiness

happiness

Tricky plurals

You know most plurals add -s (cats) or -es (boxes). Here are three more patterns:

  • Consonant + y → change y to i and add -es: berry → berries, puppy → puppies, city → cities.
  • Vowel + y → just add -s: toy → toys, day → days, monkey → monkeys.
  • Many words ending in f or fe → change to v and add -es: leaf → leaves, wolf → wolves, knife → knives, half → halves, shelf → shelves. (A few just add s, like roof → roofs.)

Some plurals are irregular. They change in a special way, or not at all:

OneMore than one
mousemice
childchildren
toothteeth
footfeet
goosegeese
personpeople
moosemoose
sheepsheep
deerdeer
Irregular plurals to learn by heart
Just for fun

One goose, two geese. So why isn't it one moose, two meese? English just loves to keep us guessing! (It's one moose, two moose.)

Worked example

Let's make plurals

Write the plurals of story, key and loaf.

  1. story ends in consonant + y (r + y): change y to i, add es: stories.
  2. key ends in vowel + y (e + y): just add s: keys.
  3. loaf ends in f: change f to v, add es: loaves.

stories, keys, loaves

consonant + ychange y to i, add esberryberriescitycitiesvowel + yjust add stoytoysdaydaysf or feoften f to v, add esleafleavesknifeknives
Three plural patterns. The underlined letters show what changes at the end of the word.

Stacking suffixes

Some words get two suffixes! care + ful + ly = carefully. help + less + ness = helplessness. Add them one at a time, and check the spelling rule at each step.

Hands-on activity

Suffix building game

You need: paper, scissors (with a grown-up's help) and a marker.

  1. Make 8 base cards: help, snow, enjoy, wash, care, sun, happy, teach.
  2. Make 8 suffix cards: -ful, -y, -ment, -able, -less, -ness, -er, -ly.
  3. Take turns picking one base card and one suffix card. Can they make a real word? If yes, write the word sum and the new word: snow + y = snowy.
  4. Check the spelling rule each time. (sun + y needs a double n!)
  5. Use your favourite new word in a sentence about winter in Canada: It was a snowy, windy day.
  6. Bonus: find a word that uses two of your suffix cards (carefully, helpfulness).

Your turn

1

Write the word sum for painless. What does it mean?

2

Add -ment to move.

3

Add -y to fog.

4

Add -able to wash. What does the new word mean?

5

Write the plural of puppy.

6

Write the plural of leaf.

7

Write the plural of child.

More practice: warm-up

1

Find the suffix in sailor.

2

Add -ful to help.

3

Write the plural of toy.

4

Write the plural of mouse.

5

Add -y to wind.

More practice: on your own

1

Add -ness to lazy.

2

Add -ly to safe.

3

Add -y to shine.

4

Write the plurals of city and day. Why are they different?

5

What does breakable mean? Use it in a sentence.

Challenge

1

Write the word sum for carefully, then for happily.

2

Which is spelled correctly: enjoiment or enjoyment? Explain.

3

Write the plurals: knife, goose, moose, berry.

Check your understanding

Quiz

1.

What does the suffix -less mean?

2.

What is sun + y?

3.

What is the plural of berry?

4.

What is the plural of wolf?

5.

Which word means a person who acts?

6.

What is hope + ful?

7.

What is the plural of mouse?

For parents and teachers

Big idea: Grade 3 students use developing knowledge of the meanings of morphemes (bases, prefixes and suffixes) to read and spell words (B2.3). Knowing that -able means "can be" helps with both meaning and spelling of washable, breakable and many more.

How to help at home:

  • Write word sums together: pay + ment = payment. Ask what the word means.
  • Spot suffixes on packaging: washable, reusable, refillable.
  • When your child misspells a suffixed word, ask: "What's the base? Does the suffix start with a vowel or a consonant?"

Common difficulties:

  • Changing y to i after a vowel (plaied, enjoiment). The y changes only after a consonant.
  • Dropping e before a consonant suffix (hopful, movment).
  • Forgetting to double (suny, fogy).
  • Plurals with apostrophes (berry's). Plurals never need an apostrophe.
  • Irregular plurals (mouses, childs). These need to be memorized; read them often.