How to Teach High Modality Words in Persuasive Writing (Years 3–6)

Read through a pile of Year 4 persuasive texts, and you’ll almost certainly find a sentence like this one:

“I think maybe kids should possibly have less homework.”

The student has an opinion, and they might even have good reasons for it. But the sentence sounds like it’s apologising for itself, so the reader isn’t convinced. Usually the problem isn’t the argument. It’s the modality.

Modality is one of the quickest wins in persuasive writing. Once students can hear the difference between “might” and “must”, their writing becomes more confident almost straight away. This guide explains what modality is, gives lists of high, medium and low modality words, and sets out a teaching sequence you can adapt for Years 3 to 6.

What is modality?

Modality is the degree of certainty, obligation, or strength in a statement. It shows how sure a writer is, or how strongly they believe something needs to happen.

Compare these three sentences:

• Dogs might be good pets.
• Dogs are probably good pets.
• Dogs are definitely the best pets.

The topic stays the same. What changes is how firmly the writer commits to the idea.

Modality isn’t limited to one type of word, which is worth pointing out to older students:

• Modal verbs: must, should, could, might, will
• Adverbs: definitely, probably, perhaps, certainly
• Adjectives: essential, likely, possible, certain
• Nouns: necessity, possibility, certainty

Most primary students start with modal verbs because they’re the easiest to spot. Adverbs and adjectives usually come next. Modal nouns tend to make sense to students around Year 6.

High, medium and low modality words

High modality	Medium modality	Low modality
must	should	might
will	would	may
always	usually	could
never	often	sometimes
definitely	probably	possibly
certainly	likely	perhaps
absolutely	ought to	unlikely
clearly	generally	seems
essential	suggest	maybe
it is vital that	it is likely that	it is possible that

Treat this list as a starting point rather than a fixed rule. Some words change depending on the sentence. “Can” often describes ability rather than certainty, and “would” behaves differently in a conditional sentence. Once students know the basic categories, move the conversation from single words to whole sentences.

Why high modality words matter in persuasive writing

A persuasive text asks the reader to accept a position. If the writer sounds unsure, the reader has little reason to agree. High modality gives a sentence authority. “Schools must provide shade over playgrounds” sounds like a demand worth taking seriously. “Schools could maybe think about some shade” sounds like a passing thought.

This matters beyond the classroom wall display. The NAPLAN persuasive writing marking guide includes persuasive devices as one of its marking criteria, and deliberate, controlled language choices are part of what markers look for. Modality isn’t the only device students need, but it is one of the simplest to teach and one where improvement is easy to see.

It also connects to the Australian Curriculum: English, which expects students to choose language that suits their purpose and audience when they create persuasive texts.

When high modality goes wrong

Many modality lessons stop too early. Once students learn that high modality is “strong”, some of them try to use it in every sentence:

“Homework is absolutely, definitely the worst thing ever and everyone always hates it.”

Piling up modality words doesn’t make an argument stronger. It makes it easier to dismiss. Words like “everyone” and “always” are claims a reader can disprove with a single example.

Skilled persuasive writers match their certainty to their evidence. A useful rule for students is:

• Use high modality for the main claim and the call to action.
• Use medium modality where the evidence is reasonable but not watertight.
• Use low modality on purpose when acknowledging the other side: “Some parents may argue that homework builds discipline. However…”

That move, called a concession, is a big step up for Year 5 and 6 writers. It shows the reader that the writer has considered other views, which makes the main argument more believable.

It’s also worth showing students that low modality isn’t a sign of weak writing. Science reports, discussion texts and information reports often use cautious language because the writer is being honest about what is and isn’t known. Modality helps students match their tone to their purpose. It isn’t a scale from bad writing to good writing.

A six-step teaching sequence for modality

1. Start with talk before writing

Make a human continuum across the classroom. Put a “Definitely not” sign at one end and a “Definitely yes” sign at the other. Read out statements such as “It will rain tomorrow” or “Our class should get an extra ten minutes at lunch”, and have students stand where their opinion sits.

Then hand out word cards (might, must, probably, never, usually) and ask students to place the words themselves along the line. They won’t always agree, and that’s useful. A question like “Is should stronger than will?” is exactly the conversation you want.

2. Build a modality word wall

Keep the sorted words where students can see them during independent writing. A three-column display for high, medium and low modality gives students something to look at when they’re stuck for a word. You can make your own with cardboard and markers, or use a printable set such as these levels of modality posters, word wall cards and worksheets.

3. Find modality in real texts

Real-world texts work better than invented examples. Letters to the editor, school newsletters, council notices, advertisements and even cereal boxes are full of modal language. Have students highlight modality words in three colours, then ask why the writer chose “must” in one place and “may” in another.

4. Turn the volume up and down

Give students a sentence and ask them to rewrite it twice, once stronger and once more cautious.

• Original: The canteen could sell healthier food.
• Turned up: The canteen must sell healthier food.
• Turned down: The canteen might consider selling a few healthier options.

Then discuss which version suits a letter to the principal and which suits a class discussion. Students learn that the “best” modality depends on who is reading and why.

5. Write first, then revise for modality

Ask students to draft without worrying about word choice, then do a separate revision pass where they highlight every modality word. Give them three questions to check:

• Is my main claim written with high modality?
• Have I included at least one counterargument using lower modality?
• Have I piled up modality words or used “always” and “never” carelessly?

Keeping drafting and revising separate stops students from getting stuck on single words before their ideas are on the page. These three questions also work well as success criteria. If you already write success criteria for your lessons, learning intentions and success criteria templates make them quick to display.

6. Take it into speaking

Persuasive speeches and class debates make modality something students can hear. “We must act now” sounds very different from “We could act at some point”, and students notice the difference in tone much faster when they say it aloud. It pairs well with explicit teaching of public speaking and active listening skills, so students learn to deliver an argument as well as write one.

Adjusting modality lessons for each year level

Year 3: Focus on a few modal verbs: must, should and might. Keep most of the work oral, and sort words into “strong” and “not so strong” before introducing a middle category.

Year 4: Add the medium category and introduce adverbs such as probably, definitely and perhaps. Real-world texts become especially useful at this level.

Year 5: Bring in modal adjectives and nouns, and start talking about matching certainty to evidence. This is a good time to practise timed persuasive writing tasks.

Year 6: Teach concession explicitly, with low modality used on purpose. Students can also analyse how editorials and advertisements shift between levels of certainty to influence readers.

Common mistakes to look out for

Piling up modality words. “Definitely absolutely must” is one idea said three times. Encourage students to pick the single word that does the job.

Confusing modality with emotive language. “Devastating” and “heartbreaking” are emotive words, not modal ones. Both are persuasive devices, but they do different jobs. One makes the reader feel something. The other shows how certain the writer is.

Verb errors after modal verbs. When students swap modal verbs in and out, the verb that follows sometimes goes wrong, as in “We must went” or “They should of”. A quick review of regular and irregular verb tenses helps here.

Repeating the same word. A text with “must” twelve times loses its force. Show alternatives such as “it is essential that”, “clearly” and “there is no doubt that”, and encourage students to vary their sentence types at the same time.

Bringing it together

Modality gives students control over how their writing sounds. A student who knows when to say “must” and when to say “might” is choosing their words on purpose, and that matters well beyond persuasive writing.

Start small with talk and word sorting, build up to revision, and keep coming back to one question: how sure do you want your reader to think you are? For more ideas on planning a writing unit, these tips for preparing an engaging English lesson plan are a useful companion. You can also browse more English teaching resources from Resources for Teaching aligned to the Australian Curriculum.