IELTS word formation: the essentials

Do you learn long lists of vocabulary for IELTS, only to forget most of the words a few days later?

One way to build your vocabulary more efficiently is to learn word families instead of individual words.

For example, instead of learning just predict, learn:

prediction → predictable → predictably

You’ve now learned three related words, and you’re much more likely to recognise them when they appear in the IELTS test.

In this Essentials Guide, you’ll learn the basic principles of word formation and how they can help you improve your IELTS vocabulary.

1. What is word formation?

Word formation is the way we create different words from a root word.

Look at this word family:

• employ (verb)
• employment (noun)
• employer (noun: person)
• employee (noun: person)
• employable (adjective)
• unemployment (negative noun)

The meaning changes depending on what we add to the root word.

These additions are usually called prefixes and suffixes.

A prefix comes before the root:

un + employment → unemployment

A suffix comes after the root:

employ + ment → employment

Learning these patterns can help you work out the meaning and grammatical form of unfamiliar words.

2. Learn word families, not individual words

When you learn a new IELTS word, don’t stop at the first form you find.

Try to find its other common forms.

For example:

• compete → competition → competitive → competitively
• differ → difference → different → differently
• vary → variation → variable → variably
• succeed → success → successful → successfully

You don’t necessarily need to learn every possible form.

Focus on the forms that are common and useful.

💡 Vocabulary tip: Whenever you write down a new word, leave some space around it for other members of its word family.

3. Look for common suffixes

Suffixes can give you clues about what type of word you’re looking at.

Nouns

Common noun endings include:

-tion / -sion
educate → education
decide → decision

-ment
develop → development
achieve → achievement

-ity
possible → possibility
responsible → responsibility

Adjectives

Common adjective endings include:

-able / -ible
predict → predictable
access → accessible

-al
environment → environmental

-ive
effect → effective

Adverbs

Many adverbs are formed by adding -ly:

significant → significantly
considerable → considerably
dramatic → dramatically

Recognising these endings is particularly useful when you need to decide what type of word fits a gap.

4. Use prefixes to change meaning

Prefixes usually change the meaning of a word rather than its grammatical form.

For example:

• possible → impossible
• agree → disagree
• regular → irregular
• understand → misunderstand

Negative prefixes can be tricky because English doesn’t use the same prefix with every word.

For example:

• unlikely
• impossible
• illegal
• irregular
• inaccurate

This is why it’s better to learn vocabulary in families and patterns rather than trying to apply one rule to every word.

5. Watch out for spelling changes

Word formation isn’t always as simple as adding a suffix.

Sometimes the spelling changes:

• possible → possibility
• happy → happiness
• decide → decision
• strong → strength

These changes can cause problems in IELTS Listening, where your answer must be spelled correctly.

They also matter in Writing, where using the wrong form of a word can affect your grammatical accuracy.

6. Don’t forget pronunciation

Words in the same family don’t always sound exactly the same.

Sometimes the word stress changes:

📸 PHOtograph → phoTOGraphy → photoGRAphic

Sometimes the pronunciation changes in less obvious ways too.

This is another reason why it’s useful to learn a word as part of a family rather than simply memorising its spelling and meaning.

When you add a new word to your vocabulary notebook, check:

• What does it mean?
• What type of word is it?
• What other forms does it have?
• How is it pronounced?

7. Why does word formation matter in IELTS?

Word formation can help you in all four parts of the IELTS test.

🎧 Listening: You need to recognise the word you hear and spell it correctly.

📖 Reading: Recognising a root word can help you work out the meaning of unfamiliar vocabulary.

✍️ Writing: You need to choose the correct grammatical form and use a range of vocabulary accurately.

🗣️ Speaking: Knowing word families gives you more flexibility when expressing your ideas.

It can also help you avoid repetition.

Instead of trying to memorise hundreds of unrelated words, you’re building networks of vocabulary that you can recognise and use in different contexts.