Grade by Grade
B. Foundations of Language · Foundations: Speaking, Listening, Words and Fluency

Word Families That Shift: How Suffixes Change Sound, Stress and Spelling

B2.1 B2.2About 45 minutes
Learning goals
  • I can read complex words accurately even when adding a suffix changes the stress or the vowel sound.
  • I can use a related word to figure out a tricky spelling (for example, a hidden vowel or a silent letter).
  • I can predict common spelling changes when suffixes like -tion, -sion, -ity and -ic are added.
  • I can recognize word families even when they don't sound alike, and use them to understand meaning.

Words to know

word family
A group of words built from the same base or root, like nation, national, nationality.
stress
The extra force on one syllable in a word: in PHO-to-graph, the first syllable is stressed.
schwa
The short, unclear vowel sound "uh" in an unstressed syllable, like the a in about. It can be spelled with any vowel.
silent letter
A letter you write but don't pronounce, like the g in sign.
related word strategy
Using a word from the same family, where a sound is clearer, to help spell or pronounce a tricky word.

Remember from earlier grades

In Grade 5 you built word matrices and saw that word families keep their spelling even when the sound changes: sign → signal, muscle → muscular, nature → natural. In Grade 7 you peeled suffix chains like formalization. Grade 8 puts it all together: you'll read and spell long words where adding a suffix moves the stress, changes a vowel or consonant sound, or changes the spelling. Knowing the pattern makes these words automatic.

Let's start with a puzzle

Say these three words aloud: photograph, photography, photographic.

They're one family. They share the same parts: photo (light) + graph (write, record). But they sound surprisingly different. The stressed syllable moves each time you add a suffix, and the vowels change with it:

  • PHO-tuh-graf
  • fuh-TOG-ruh-fee
  • foh-tuh-GRAF-ik

English spelling often keeps the family looking the same even when it sounds different. That's good news: once you see the family, you can read the meaning right away.

photographPHOtographphotographyphoTOGraphyphotographicphotoGRAPHicFilled box = stressed syllable
photograph, photography, photographic: the stressed syllable (filled) moves from the first syllable to the second to the third as suffixes are added.

Four kinds of shifts

1. The stress moves. Some suffixes pull the stress toward them. Watch for -ic, -ity, -ical, -ian, -tion:

  • ATH-lete → ath-LET-ic; DEM-o-crat → de-MOC-ra-cy → dem-o-CRAT-ic; PER-son → per-son-AL-i-ty.

2. A vowel sound changes (but the spelling doesn't). A long vowel often becomes short:

  • nation → national (long a → short a), volcano → volcanic, compete → competitive, sane → sanity, wise → wisdom.

3. A consonant sound changes (but the spelling doesn't).

  • electric (k) → electricity (s); music (k) → musician (sh); critic (k) → criticize (s).

4. The spelling changes. Some patterns you can learn:

  • -de or -t → -sion: decide → decision, explode → explosion, permit → permission.
  • -ceive → -cept-: receive → reception, deceive → deception.
  • -be → -ption: describe → description.
  • A vowel drops: explain → explanation, pronounce → pronunciation, maintain → maintenance, exclaim → exclamation.
Tricky wordHidden soundRelated word that reveals it
democracy (the a is unclear)schwademocratic (the a is clear)
grammar (the a at the end sounds like er)schwagrammatical (the a is clear)
history (the o is unclear)schwahistorical
composition (the second o is unclear)schwacompose
signsilent gsignature, signal
autumnsilent nautumnal
condemnsilent ncondemnation
musclesilent cmuscular
The related word strategy: when a sound is unclear or silent, think of a family member where you can hear it.
Tricky wordthink of a relativeNow you can hear itsignsilent gsignatureg soundedmusclesilent cmuscularc soundedgrammarunclear agrammaticalclear a
The related word strategy: when a letter is silent or unclear, a family member where you can hear it tells you how to spell it.
Worked example

Let's read and spell with word families

  1. Read aloud: democratic, criticize, pronunciation.
  2. Spell the hidden vowel: hist_ry and leg_l.
  1. democratic: it's in the family of democracy and democrat. Peel: demo (people) + crat (rule) + -ic. The suffix -ic pulls the stress to the syllable just before it: dem-uh-KRAT-ik.
  2. criticize: from critic. The c at the end of critic says /k/, but before -ize (an i), it says /s/: KRIT-ih-size.
  3. pronunciation: from pronounce, but the spelling changes: pronounce loses its o in the second syllable. Read it pruh-nun-see-AY-shun (not pro-NOUNCE-iation). Many people, even adults, misspell this word!
  4. hist_ry: say a relative: his-TOR-i-cal. You can clearly hear the o, so it's history.
  5. leg_l: say a relative: le-GAL-i-ty. You can hear the a, so it's legal.

democratic: dem-uh-KRAT-ik; criticize: KRIT-ih-size; pronunciation: pruh-nun-see-AY-shun. The hidden vowels are history and legal.

Meaning first, then sound

When you meet a long word, don't try to sound it out letter by letter. Find the family first (electric in electricity), then adjust the sound. When you spell, think of a relative where the tricky sound is clear.

Just for fun

Fun fact: in some English words, moving the stress turns a noun into a verb. You can re-CORD a REC-ord, pre-SENT a PRES-ent, and ob-JECT to an OB-ject. Same spelling, different word!

Hands-on activity

Word family shift cards

You need: 12 index cards or scrap paper, a pencil, and a family member to quiz you.

  1. Write one word on the front of each card: nation, athlete, electric, music, decide, permit, receive, describe, explain, pronounce, sign, grammar.
  2. On the back, write a family member with a suffix: national, athletic, electricity, musician, decision, permission, reception, description, explanation, pronunciation, signature, grammatical.
  3. Shuffle. Your family member shows you the front; you say and spell the related word. Then flip to check.
  4. For each card, decide which shift happened: stress, vowel sound, consonant sound or spelling (some have more than one).
  5. Sort the cards into piles by type of shift. Which pile is biggest?
  6. Bonus: find three more families in a book or around the house (for example, on a food label: nutrition → nutritious).

What to look for: correct spelling and pronunciation of each related word, and a sensible label for each shift. For example, nation → national is a vowel shift; decide → decision is a spelling and consonant shift; sign → signature reveals a silent letter.

Your turn

1

Say both words and mark the stressed syllable: athlete, athletic.

2

What sound does the c make in electric? In electricity?

3

Use a related word to spell the silent letter: mus_le.

4

Add -sion: explode → ?

5

Add -tion: explain → ?

6

Which is spelled correctly: pronounciation or pronunciation?

7

Use a related word to fill in the hidden vowel: gramm_r.

More practice: warm-up

1

What is a word family?

2

Add -ian to music.

3

Add -ion to permit (watch the spelling).

4

Which letter is silent in sign?

5

What is a schwa?

More practice: on your own

1

Write the noun form of receive and explain the spelling pattern.

2

Say and compare volcano and volcanic. What changes?

3

Use a related word to spell: autum_ (the season).

4

Explain why compete and competition look alike even though they sound different.

5

Change to a noun: maintain → ? (be careful).

Challenge

1

Read these aloud and mark the stress: democrat, democracy, democratic.

2

A classmate spells definate. Use a related word to prove the correct spelling.

3

Explain why knowing sign helps you read signature, resign and designate, even though they sound different.

Check your understanding

Quiz

1.

In photography, which syllable is stressed?

2.

Which related word helps you spell the silent letter in condemn?

3.

Add -sion to decide:

4.

The c in electricity sounds like...

5.

Which spelling is correct?

6.

Which pair shows a vowel sound change with the same spelling of the base?

For parents and teachers

Big idea (B2.1, B2.2): Grade 8 students use consolidated morphological knowledge to read and spell complex words accurately and automatically. Many long words change their stress, vowel or consonant sounds, or spelling when suffixes are added; recognizing the word family lets students read the meaning and choose the spelling. (Spelling conventions are also practised in the companion unit Foundations of Writing.)

How to help at home:

  • When your child misspells a word with an unclear vowel, ask: "Can you think of a relative where you can hear that vowel?"
  • Play "family shift": you say a word (electric), they give a relative (electricity) and say what changed.
  • Read long words in the news aloud together and find the family.

Common difficulties:

  • Pronouncing a new word with the base's stress (pho-TO-graph-y). Practise saying families in a row.
  • Keeping a dropped letter (pronounciation, explaination, maintainance).
  • Sounding out letter by letter. Encourage finding the base first, then adjusting the sound.