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Formal vs Informal Language in IELTS Writing

IELTS Writing29 August 2026 · 7 min read · WiderAI Team

IELTS Writing Task 2 and Academic Task 1 should be written in a formal, academic style: no contractions, no conversational phrases, no idioms, and a measured, impersonal tone. The one deliberate exception is the General Training Task 1 letter, where the tone must match the recipient — formal for a manager or a company, informal for a friend — and choosing the wrong register is itself an error.

Formality is not a separate score, but it leaks into two criteria at once. Vocabulary is judged partly on whether your word choices suit the context, so kids, stuff and a lot of in an academic essay count against you the same way a wrong word would. And the task itself expects a particular register: an essay that chats with the reader has not fully done what the task asked, and a GT letter to a friend written like a legal notice has missed the point of the task entirely.

The good news is that register is one of the fastest things to fix in IELTS Writing. It is not a grammar system you need years to absorb; it is a finite list of habits to drop and swaps to learn. Most candidates can clean up their register in a couple of weeks of deliberate editing.

What makes writing sound informal?

Informality is rarely one big mistake — it is an accumulation of small conversational habits. These are the ones examiners see constantly:

• Contractions: don't, it's, can't, they're. Write the full forms in essays, always. This is the easiest rule in IELTS and the most commonly broken.
• Conversational vocabulary: kids, stuff, things, guys, a lot of, loads of, big, get, really, pretty (as in "pretty good"). None of these is wrong English; all of them belong in speech.
• Phrasal verbs with everyday flavour: look into, put up with, get rid of, come up with. Formal single-verb equivalents exist for most: investigate, tolerate, eliminate, devise. Not every phrasal verb is informal — carry out and result in are fine in academic prose — but when a Latinate verb exists, essays usually prefer it.
• Idioms and clichés: at the end of the day, a double-edged sword, every coin has two sides. Idioms are rewarded in Speaking and penalised by effect in essays, where they read as memorised filler.
• Talking to the reader: you know, let's think about, as you can see, don't you think? An essay argues to a general audience; it does not converse with one person.
• Exclamation marks and rhetorical drama: How can this be allowed! Academic style makes claims calmly and supports them.
• Vague sentence-starters: Well, So, Anyway, By the way. Replace with real linkers or simply delete them.

Notice what is not on the list: personal opinion. "I believe" and "In my view" are perfectly acceptable in Task 2 — the question explicitly asks for your opinion. Formality concerns how you express ideas, not whether you may own them.

Which formal alternatives should you learn?

Learn swaps as pairs, because in the exam you need the formal option to arrive automatically. A short starter set:

• a lot of / lots of → many, a great deal of, considerable
• kids → children; guys / people like that → individuals, members of the public
• get → obtain, receive, become (choose by meaning — get worse → deteriorate)
• big / huge → significant, substantial, considerable
• good / bad → beneficial, effective / harmful, detrimental
• think about → consider; find out → determine, discover
• more and more → increasingly, a growing number of
• nowadays is acceptable, but these days leans conversational — currently or in recent years is safer

Two warnings. First, swap by meaning, not by reflex: obtain a cold is nonsense, and a mechanical swap that produces an unnatural collocation costs more than the informal original. Second, the goal is appropriate, not impressive. A precise common word always beats a grand word used slightly wrongly.

Can writing be too formal?

Yes, and examiners see this failure as often as informality. It has two forms.

The first is inflated vocabulary: plethora, myriad, utilize, plebeian, in this day and age, it is an incontrovertible fact that. Candidates learn these as "band 9 words", then deploy them in slightly wrong contexts, and the effect is the opposite of the one intended. Examiners reward precision and naturalness; a script stuffed with ornamental vocabulary that does not quite fit signals memorisation, and memorised language earns little credit anywhere in IELTS.

The second is the prefabricated frame: openings like In the contemporary epoch, it is universally acknowledged that the issue of X has sparked heated debate — thirty words that could preface any topic on earth and say nothing about this one. Examiners meet these sentences daily and skim past them; the words you spent on the frame earn nothing, and the essay's real content starts a sentence late.

The reliable register for Task 2 sits in the middle: plain, precise, complete sentences with no conversational habits. Think of how a good textbook explains something — serious without ceremony. If a sentence would survive in a broadsheet editorial, it will survive in your essay.

How does tone work in General Training letters?

The GT Task 1 letter is the one IELTS writing task where informal language can be the correct answer. The prompt tells you who the reader is, and tone appropriateness is assessed directly.

• Formal letters (a company, a manager you name as Sir/Madam, a council): no contractions, no idioms, conventional openings and closings — Dear Sir or Madam … Yours faithfully. State your purpose in the first sentence.
• Semi-formal letters (a landlord or neighbour you know by name): polite and restrained, but Dear Mr Karimov and a warmer sign-off are natural. Contractions are best still avoided.
• Informal letters (a friend): contractions, phrasal verbs and a chatty opening are not merely allowed — their absence is an error of tone. Dear Aziz, Great to hear from you! is right; Dear Sir, I am writing to inform you of my forthcoming visit to your best friend is wrong.

The skill being tested is consistency: pick the register the recipient demands and hold it from greeting to sign-off. A friendly letter that suddenly goes bureaucratic in paragraph two loses marks for exactly the same reason an essay with gonna in it does.

Is Speaking judged by the same rules?

No — and mixing up the two registers costs candidates in both papers. IELTS Speaking is an informal conversation: contractions, phrasal verbs and idiomatic language used naturally are strengths there, and answering like a written essay makes you sound rehearsed. The full picture of what examiners reward in the interview is in our guide to the speaking band descriptors explained.

The practical rule: keep two registers in your toolkit and label your vocabulary as you learn it. When you note a new phrase, mark it essay, speaking, or both. Candidates who never label end up writing loads of benefits in Task 2 and saying it is imperative that in Part 1 — each perfectly good language, each in the wrong room.

Register, more than almost anything else in IELTS Writing, rewards editing. Draft your practice essays freely, then hunt the informalities afterwards and keep a list of the ones you personally produce. After ten essays the list stops growing — and the habit is fixed long before exam day.