Year 6 English · Key Stage 2 · Vocabulary, grammar and punctuation – English Appendix 2

Year 6 formal and informal English, synonyms and antonyms

In Year 6, children learn that the words and sentence patterns we use when chatting are often not the ones we choose for a letter, a report or a speech. They study the difference between informal and formal vocabulary and structures, and how words are related by meaning as synonyms (similar meaning) and antonyms (opposite meaning). The aim is a writer who chooses words on purpose, not one who simply reaches for long ones.

Formal language, synonyms and antonyms, explained

Everybody already switches between formal and informal language without thinking about it. You speak to a friend differently from the way you speak to a head teacher, and you would write a message to a cousin differently from a letter to a council. Year 6 gives children the terms to describe that switch and the skill to do it deliberately in writing. Informal language is relaxed and close to speech: contractions such as don’t and we’ve, chatty phrases such as find out or ask for, and short, loose sentences. Formal language is more careful and precise, and is used for reports, letters of application or complaint, explanations and speeches.

In vocabulary, schools choose their own examples, and many compare pairs such as find out and discover, ask for and request, or go in and enter. Often the formal choice is a single verb where the informal one is a verb plus a small word, though not always, and a long word is not automatically a formal one. A useful test is to ask who is reading and what they would expect. Children are also taught that formal writing usually avoids slang, contractions and chatty asides to the reader, while informal writing, such as a character’s dialogue in a story, is allowed to use all of them.

Sentence patterns change as well as words. Question tags, the little questions added to the end of a statement, belong to speech: “He’s your friend, isn’t he?” In formal writing the author simply states the point: “He is your friend.” Many schools also introduce the subjunctive, a verb form that appears in very formal writing and speech. “If I were you” is the formal form where many people say “If I was you”, and “Were they to arrive early, we would begin” is a very formal way of saying “If they arrived early, we would begin”. Many schools treat the subjunctive as something to recognise and try out in very formal writing, rather than something to use all the time.

The second half of the topic is about how words relate to each other. A synonym is a word with a similar meaning to another; an antonym is a word with the opposite meaning. Big, large and enormous are synonyms of one another, and big and small are antonyms. The word similar matters, because synonyms are rarely identical. Enormous is stronger than large, and slim sounds kinder than skinny. Choosing between them is about shades of meaning, and about register, which means how formal a word feels. Teachers often ask children to arrange synonyms from weakest to strongest, for example chilly, cold, freezing.

In May of Year 6 children may meet questions in the national grammar, punctuation and spelling test asking them to pick the formal version of a sentence or to find a synonym or antonym. The real value, though, is in their own writing. A child who can lift a sentence up a notch for a letter, then relax it again for a character’s speech, has a flexibility that helps in every subject.

Words your child will hear

Formal: Careful, precise language used with people you don’t know well or in serious writing, such as a letter to a head teacher.
Informal: Relaxed, everyday language used with friends and family, with contractions and chatty phrases.
Register: How formal or informal a piece of language is, chosen to suit the reader and the purpose.
Synonym: A word with a similar meaning to another word. Discover is a synonym of find out.
Antonym: A word with the opposite meaning. The antonym of hot is cold.
Question tag: A short question added to a statement, as in “It’s late, isn’t it?”. Common in speech, rare in formal writing.
Subjunctive: A verb form used in very formal English for wishes and unlikely situations, such as “If I were you”.

What the National Curriculum says

The programme of study for Year 6 says:

Pupils should be taught the difference between vocabulary typical of informal speech and vocabulary appropriate for formal speech and writing
Pupils should be taught how words are related by meaning as synonyms and antonyms
Pupils should be taught the difference between structures typical of informal speech and structures appropriate for formal speech and writing
Pupils should be taught to recognise and use the grammatical terminology: synonym, antonym

Objectives from the National Curriculum in England, © Crown copyright, used under the Open Government Licence v3.0.

Try it: from a quick message to a formal letter

A pupil has written this note about a cancelled school trip: “Hi, we found out the trip’s off, so we can ask for our money back, can’t we?” Rewrite it as the opening of a formal letter to the head teacher.

Decide who is reading and why. The reader is the head teacher and the purpose is a polite request, so the register should be formal. Then underline the informal parts: “Hi”, “found out”, “the trip’s off”, “ask for”, the contraction “trip’s” and the question tag “can’t we”.
Swap the vocabulary. “Found out” becomes “discovered”. “The trip’s off” becomes “the trip will not take place”. “Ask for” becomes “request”. “Hi” becomes “Dear Headteacher,”.
Change the structure. The question tag “can’t we” asks the reader to agree, which sounds like speech. Drop the tag and state clearly and politely what the writer wants: “we would like to request a refund”.
Check the shade of meaning. Request, ask for and demand are all close in meaning, but demand is much stronger and would sound rude. Request is polite and formal, so it is the best synonym here.
Read the new version aloud and listen for any contractions or chatty words left behind.

Dear Headteacher, We have discovered that the trip will not take place, and we would like to request a refund.

Common mistakes and how to help

Believing formal writing means long, complicated words

Children want to sound grown up, so they swap simple words for “utilise” or “commence” and end up with clumsy sentences that are harder to read.

What helps: Explain that formal means appropriate and precise, not fancy. “Use” is perfectly formal. Ask your child to read the sentence aloud and decide whether the reader would find it natural.

Thinking synonyms mean exactly the same, so any one will do

A thesaurus lists words together, which makes them look interchangeable. “The soup was warm” and “The soup was scorching” are very different sentences.

What helps: Put the new word into the sentence and ask what has changed. Arrange a set of synonyms from weakest to strongest so the shades of meaning become visible.

Treating informal language as wrong or lazy

After a term of learning about formal writing, children can start to correct everyday speech, or remove contractions from a character’s dialogue.

What helps: Make clear that both are right in the right place. Informal words give a story character a voice. The skill is matching language to reader and purpose.

Making an antonym by adding un- or not

Happy and unhappy do work, so children assume every word can be opposed in the same way, and invent words such as “unbig” or “unfast”.

What helps: Collect antonym pairs that use different words, such as hot and cold or big and small. Point out that some words have several antonyms: the opposite of good might be bad or poor, depending on the sentence.

How to help at home

Switch the register. Ask your child to say a message to a friend, such as asking to borrow a game, then re-say it to a grandparent or a shop assistant. What changed? Words, tone and sentence shape are all fair answers.
Build a ladder of words. Pick a word such as tired and write synonyms on strips of paper from weakest to strongest: sleepy, tired, weary, exhausted. Argue about the order, because the arguing is where the learning happens.
Spot formal writing around the house. Compare a school newsletter, a letter from the council or a notice at the leisure centre with a text message. Ask your child to find two formal words and one informal phrase.
Play opposites ping-pong. Call out a word and take turns giving an antonym. When a word has more than one, such as cool or cold for hot, keep going until you run out. It makes a good game for car journeys.
Write a polite request. Your child writes a short formal note asking a relative for something real, such as a lift to a party. Read it together and swap any chatty phrases for more careful ones.

Updated 20 October 2026.