Grade by Grade
B. Foundations of Language · Listening, Speaking and Word Power

Suffixes for Grade 4: -tion, -ous, -ive, -al, -ible, -ity and More

B2.1 B2.2About 45 minutes
Learning goals
  • I can read and explain the suffixes -tion/-sion, -ous, -ive, -al, -ible, -ity, -en and -ward.
  • I can tell how a suffix changes a word's meaning or job.
  • I can read words where the sound of the base changes when a suffix is added.
  • I can read and understand words with more than one suffix.

Words to know

suffix
A morpheme added to the end of a base.
noun
A word that names a person, place, thing or idea.
adjective
A word that describes a noun.
verb
An action or being word.
stress
The syllable you say a little louder and longer, like NA in NA-tion.

Remember from Grade 3

In Grade 3 you learned -able (can be), -ment (the act or result of), -er/-or and -ist (a person who), -ful (full of), -less (without), -ness (the state of being) and -ly (in a ___ way). You also saw that a suffix can change a word's job: move (verb) → movement (noun) → movable (adjective).

In Grade 4 you'll learn suffixes that turn up in longer, more grown-up words, like celebration, dangerous, creative and electricity.

Let's start with one base

Look how many words come from create:

  • create (verb): to make something new
  • creation (noun): something that was made
  • creative (adjective): good at making new things
  • creativity (noun): the ability to make new things
  • creatively (adverb): in a creative way

One base, five words! Suffixes do the work.

createverbcreationnouncreativeadjectivecreativitynouncreativelyadverb+ ion+ ive+ ity+ lyThe final e drops before -ion, -ive and -ity.
One base, five words. Each suffix changes the word and its job (verb, noun, adjective, adverb).
SuffixMeaningExamplesUsually makes a...
-tion, -sion, -ationthe act, process or result ofaction, celebration, decision, inventionnoun
-ousfull of, havingdangerous, famous, joyous, poisonousadjective
-ivetending to, able toactive, creative, protectiveadjective
-alhaving to do withmusical, natural, seasonal, nationaladjective
-iblecan be (like -able)flexible, reversible, collapsibleadjective
-itythe state or quality ofequality, reality, electricitynoun
-ento make, to becomebrighten, shorten, widenverb
-wardin the direction ofbackward, upward, homewardadverb or adjective
Suffixes for Grade 4
Worked example

Let's use a suffix to understand a word

Read: The waterfall was dangerous after the spring thaw. What does dangerous mean?

  1. Peel off the suffix: -ous (full of, having).
  2. The base is danger.
  3. Add the meanings: full of danger.
  4. Check: after the snow melts, the water is high and fast, so it's not safe. ✅

dangerous = danger + ous: full of danger, not safe.

Listen: the base can change its sound

With some suffixes, the spelling of the base stays almost the same, but the sound changes. Don't let it trick you! Trust the meaning parts.

  • act → ac-tion: the t + ion sounds like "shun."
  • de-CIDE → de-CI-sion: the s + ion sounds like "zhun."
  • NA-tion → NA-tion-al: the first a changes from "ay" to a short "a" (NASH-un-ul).
  • e-LEC-tric → e-lec-TRIC-i-ty: the c changes from a "k" sound to an "s" sound, and the stress moves.

If a word sounds strange, ask: Do I know a word with the same base?

Same base, new sound: the filled box is the stressed (loudest) syllable.eLECtricelecTRICityc now says /s/, and the stress movesdeCIDEdeCIsions + ion says "zhun"ACTACtiont + ion says "shun"
When a suffix is added, the sound of the base can change, but its meaning stays.
Worked example

Let's read a word where the sound shifts

Read: The storm knocked out the electricity for two days.

  1. Peel off the suffix: -ity (the state or quality of).
  2. The base looks like electric.
  3. Read the parts: e-lec-tric + i-ty. The c before i says "s": e-lec-TRIS-i-tee.
  4. Meaning: electric power, the energy that runs lights and fridges.
  5. Check: a storm knocked out the power. ✅

electricity = electric + ity. The base's sound changed, but its meaning didn't.

Worked example

Let's read a word with two suffixes

Read: The championship game was shown nationally on TV. What is the word sum for nationally?

  1. Peel off -ly (in a ___ way).
  2. Peel off -al (having to do with).
  3. The base is nation (a country). Inside nation is another suffix, -ion, but nation is the base we know.
  4. Word sum: nation + al + ly → nationally.
  5. Meaning: in a way that has to do with the whole nation, across the whole country.

Games shown nationally are shown across the whole country.

-able or -ible?

Both mean can be. Many -able words have a whole base word you know (breakable, washable). Many -ible words have a base that isn't a whole English word on its own (visible, edible). This is a helpful pattern, not a perfect rule, so check a dictionary when spelling.

Just for fun

Try this suffix tongue twister three times fast: The creative creator's creation was created creatively.

Hands-on activity

Suffix sorting race

You need: 16 index cards or paper squares, a marker, a timer and a partner.

  1. Write these words, one per card: celebration, famous, active, musical, flexible, equality, brighten, upward, decision, joyous, protective, seasonal, reversible, reality, widen, homeward.
  2. Make labels: -tion/-sion, -ous, -ive, -al, -ible, -ity, -en, -ward.
  3. Set the timer for 2 minutes. Sort each word under its suffix. Two cards go under each label.
  4. For each word, say the base and the meaning: "widen: wide + en, to make wider."
  5. Switch: your partner sorts while you time. Who was faster?

Your turn

1

What does -ous mean? Read joyous.

2

Find the base and suffix in protective.

3

Write the word sum for celebration.

4

What does brighten mean?

5

Read seasonal. What does it mean?

6

What does flexible mean?

7

Read upward. Which way is it?

More practice: warm-up

1

What does -al mean?

2

What does -en mean?

3

Find the suffix in famous.

4

Find the suffix in equality.

5

What does homeward mean?

More practice: on your own

1

Write the word sum for creative and show the spelling change.

2

Change decide into a noun using a suffix. How does the sound change?

3

Read: The mountain trail was narrow, so they had to widen it. What does widen mean, and what job does it do in the sentence?

4

Which word means the state of being equal: equally or equality?

5

Read poisonous. Is it an adjective or a noun? How do you know?

Challenge

1

Write the word sum for creatively, then explain the meaning by building it one part at a time.

2

Explain why national and nation sound different even though they share a base. How can noticing the base help you?

3

Make four words from the base invent using suffixes. Tell what each means.

Check your understanding

Quiz

1.

What does -ous mean in famous?

2.

Which word is a noun?

3.

What does shorten mean?

4.

What is the base in electricity?

5.

Which suffix means in the direction of?

6.

What does reversible mean?

7.

Which word sum is correct?

For parents and teachers

Big idea: Grade 4 B2.1 and B2.2: using suffixes (and other morphemes) to read words and work out their meaning. Many Grade 4 suffixes come from Latin and appear in content-area words (erosion, habitat topics, national parks, equality). A key Grade 4 idea is that the sound of a base can change while its meaning and most of its spelling stay (nation/national, electric/electricity).

How to help at home:

  • Build "word trees" on paper: a base in the trunk (act) and branches for each form (action, active, activity, actor, react).
  • When your child stumbles on a long word, cover the suffix with a finger, read the base, then uncover.

Common difficulties:

  • Not recognizing a base whose sound changes (nation/national). Say both words, then point to the shared letters.
  • Confusing -ly (adverb) and -ity (noun). Use each in a sentence.
  • -able vs. -ible. For reading, both mean "can be"; spelling is practised in the writing unit.