When should I write formally and when can I be informal, and how do I tell the difference in my word choices?
Choose between formal and informal language to suit the purpose, audience and context, and adjust word choice, contractions and tone to match
How to choose between formal and informal language in N(A)-Level English to suit the purpose, audience and context, adjusting word choice, contractions and tone so a letter, email or essay sounds right.
Reviewed by: AI editorial process; not yet individually human-reviewed
Have a quick question? Jump to the Q&A page
Jump to a section
What this dot point is asking
English changes depending on who you are writing to and why. Writing to a principal is not the same as texting a friend. SEAB calls this matching your register to the purpose, audience and context, and it is central to Situational Writing, where you might write a formal letter one year and a friendly email the next. This dot point is about telling formal from informal language and adjusting your word choice, your contractions and your tone so the writing sounds right for the situation.
The answer
Register is matching language to the situation
"Register" simply means the level of formality you use. The same idea can be said formally or informally: "I am writing to enquire about the trip" versus "I just wanna ask about the trip." Neither is wrong in itself; what matters is whether it fits the reader and the purpose. A formal letter needs formal language; a message to a close friend can be relaxed.
How formal and informal language differ
Three things change between the two:
- Word choice. Formal English uses full, precise words: enquire, purchase, however, request. Informal English uses casual words and slang: ask, buy, but, stuff, kinda.
- Contractions. Informal writing uses contractions freely (I'm, don't, can't). Formal writing usually spells them out (I am, do not, cannot).
- Tone. Formal writing is polite and a little distant. Informal writing is warm and chatty, and may use exclamation marks and friendly openings.
Decide by purpose, audience and context
Before you choose, ask three quick questions. Who is the reader (a principal, a company, a friend)? Why are you writing (to complain, to apply, to invite, to thank)? Where does the writing belong (an official letter, a school email, a personal note)? A complaint to a company is formal; an invitation to a friend is informal. Let the answers set your register before you write a word.
Keep your register consistent
Pick a register and stay with it. The common slip is starting formally and sliding into casual language partway through: "I am writing to complain about the service. It was super annoying!" The phrase "super annoying" breaks the formal tone. Read your work back and remove any word that does not match the level you chose.
When in doubt, lean formal
If you are unsure how formal to be, choose the more formal option. In an exam, the safer mistake is sounding a little too polite, not too casual. A formal register almost never offends a reader, while slang in a letter to a principal stands out immediately. Formal is the safer default for most Situational Writing tasks.
Examples in context
Example 1. A formal complaint. Writing to a shop about a faulty phone, a student uses formal language: "I am writing to express my dissatisfaction with a phone I purchased last week." The full forms, precise words and polite tone suit a complaint to a company.
Example 2. A friendly invitation. Inviting a cousin to a birthday party, the same student writes informally: "Hi Mei! I'm having a party on Saturday and I'd love you to come!" The contractions, exclamation mark and warm tone fit a message to family. Same writer, different register, each matched to the reader.
Try this
Cue. Make this formal for a letter to a teacher: "Hey, can I get more time for my project?" A good answer: "Dear Mr Lim, I would like to request an extension for my project." The slang and contraction are gone and the tone is polite.
Cue. Name two signs that a piece of writing is informal. Two signs: contractions (I'm, don't) and casual words or slang (stuff, kinda, guys). A relaxed, chatty tone with exclamation marks is another sign.
Cue. Explain why you should "lean formal" when unsure. In an exam, sounding slightly too polite rarely costs marks, while slang in a formal task stands out as a mismatch, so formal is the safer default.
Exam-style practice questions
Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
Original4 marksRewrite each informal sentence in formal English, suitable for a letter to a principal: (a) 'Hi, I wanna ask about the trip.' (b) 'The food was kinda bad.' (c) 'Thanks loads for sorting this out.' (d) 'Can you guys fix the aircon?'Show worked answer →
Sample formal versions:
(a) "Dear Sir or Madam, I am writing to enquire about the trip."
(b) "The food was rather disappointing."
(c) "Thank you very much for resolving this matter."
(d) "Could the air-conditioning please be repaired?"
What markers reward: removing slang and contractions ("wanna", "kinda", "you guys"), replacing casual words with formal ones ("ask" to "enquire", "fix" to "repair"), and using a polite, respectful tone suited to writing to a principal. A version that stays casual, even if it is grammatical, would not score.
Original3 marksExplain three differences between formal and informal language, and give one situation where each kind is appropriate.Show worked answer →
Three differences:
(1) Word choice: formal language uses full, precise words ("enquire", "however", "purchase"), while informal language uses casual words and slang ("ask", "but", "buy", "stuff").
(2) Contractions: informal language uses contractions ("I'm", "don't", "can't"); formal language usually writes them in full ("I am", "do not", "cannot").
(3) Tone: formal language is polite and a little distant; informal language is friendly and relaxed.
Appropriate situations: formal language suits a letter to a principal, a job application or a report; informal language suits a message to a close friend or a chatty email to a sibling.
What markers reward: naming real differences (word choice, contractions, tone) and matching each register to a sensible situation, showing that the choice depends on audience and purpose.
Related dot points
- Choose the right word for the meaning, telling apart easily confused words and synonyms that carry slightly different shades of meaning
How to choose the exact right word in N(A)-Level English, telling apart easily confused words and synonyms with slightly different shades of meaning, so your writing is accurate and clear.
- Build a wider and more precise vocabulary by reading, collecting useful words, and using new words accurately in your own writing
How to build a wider, more precise vocabulary for N(A)-Level English by reading regularly, keeping a word list, learning words in families, and using new words accurately so your writing earns more marks.
- Match tone and register to the audience and purpose of a situational writing task, choosing appropriate vocabulary, openings and closings for formal and informal situations
How to choose the right tone and register for a Situational Writing task, matching formality to the audience and purpose so a letter to a principal sounds different from an email to a friend.
- Identify the purpose, audience and context of a situational writing task and use them to shape the content, tone and choices in the response
How to read a Situational Writing task for its purpose, audience and context, and use those three things to decide what to write, how formal to be, and what information to include.
- Choose and lay out the correct format for a situational writing task, including the openings, sign-offs and features that each format requires
How to pick the correct format for a Situational Writing task (email, letter, report, speech) and lay it out properly with the right greeting, structure and sign-off.