Most vocabulary advice for IELTS Speaking is actively harmful. It tells you to learn impressive words and idioms, so candidates arrive with a list of proverbs and a plan to deploy plethora.
The descriptor does ask for “less common and idiomatic vocabulary” at band 7. It just does not mean what almost everyone thinks it means.
What the descriptor actually says
| Band | Lexical Resource |
|---|---|
| 5 | ”uses vocabulary with limited flexibility”; attempts paraphrase “but not always with success” |
| 6 | ”wide enough vocabulary to discuss topics at length and make meaning clear in spite of inappropriacies”; “generally paraphrases successfully” |
| 7 | ”uses vocabulary resource flexibly”; “some less common and idiomatic vocabulary”; “some awareness of style and collocation”; “uses paraphrase effectively” |
| 8 | ”wide vocabulary resource readily and flexibly to convey precise meaning”; “skilful use of less common and idiomatic items” |
Two words do the work at band 7: flexibly and effectively. Neither means rare.
Idiomatic means phrasal verbs
This is the correction worth the whole guide.
Examiners listening for “idiomatic language” are mostly listening for phrasal verbs used naturally in context — bring up, take over, switch off, chill out, put off, end up. Ordinary spoken English, produced without thinking about it.
They are not listening for proverbs. Raining cats and dogs, the ball is in your court, every cloud has a silver lining — these are what candidates memorise, and they almost always arrive slightly wrong for the moment, which reads as rehearsed rather than fluent.
Sounds learned: Regarding my hometown, every cloud has a silver lining.
Sounds fluent: I grew up there, then ended up moving away for work — I still go back whenever I can switch off for a weekend.
The second contains three phrasal verbs and no idiom, and it is the one that scores.
Less common means precise, not rare
The other half of the descriptor is about precision. You replace a generic word with the exact one, not with a longer one.
| Instead of | Say |
|---|---|
| happy | delighted |
| a good experience | a rewarding experience |
| a big problem | a serious issue, a major drawback |
| a good city | a thriving city |
| nice scenery | picturesque scenery |
| a trip to see culture | a cultural excursion |
None of those are difficult words. They are ordinary words used exactly, which is what “convey precise meaning” describes at band 8.
Topic-specific vocabulary belongs here too — sustainability and carbon footprint on an environmental question, operating system and user interface on a technology one. Enough to discuss the subject specifically, not a glossary.
There is no official IELTS vocabulary list, and no examiner ticks words off a sheet. They are judging flexibility and precision across everything you say.
The words that cost you marks
The sources name specific red flags, and they share a cause: they arrive in memorised phrasing and land slightly wrong.
Plethora. Amelioration. Especially inside constructions like “the unprecedented proliferation of technological paradigms facilitates multifaceted societal amelioration” — a sentence no person has ever said aloud.
Templated openings. “In this modern era of technology…”, “That is a highly contentious issue…” Essay language in a conversation, which is a register mismatch before it is anything else.
Words used in the wrong context. Cutting-edge applied to a person. Handsome applied to a woman. Beautiful applied to a weekend, where lovely or relaxing was meant.
Three reasons these lower the score rather than raising it:
- They sound rehearsed, and examiners are trained to spot exactly that.
- They reduce precision. Forcing a rare word into an imperfect fit is a lexical error and is marked as one.
- They cause hesitation. Hunting for the impressive word mid-sentence produces the language-related pause that separates band 6 from band 7 on Fluency too.
A simple word used correctly always beats an advanced word used oddly.
Collocation
Collocation is which words go together — heavy rain but strong wind, environmental pollution, interested in, responsible for.
Errors are marked as lexical inappropriacy: youth people for young people, serial issue for serious issue. The descriptors are explicit that at bands 6 and 7 these are tolerated as long as meaning stays clear. By band 8 they need to be accurate, with only occasional slips.
So collocation is not the thing to panic about at band 7 — but it is what separates 7 from 8, and it is learned by collecting pairs rather than single words. Record make a decision, not decision.
Never go silent
The most damaging vocabulary problem is not using the wrong word. It is stopping.
If you hit a gap and fall silent while you hunt, that pause is scored under Fluency and Coherence, and a long search for basic vocabulary can hold that criterion at band 5. The word you were looking for was worth far less than the silence cost.
So paraphrase, immediately:
- …the thing you use to — sorry, the device that measures it…
- …there’s a word for this in my language, it means something like a neighbourhood watch…
- …I can’t think of the exact term, but it’s the person who checks the accounts.
Paraphrase is not an admission of weakness. It appears in the descriptor at every band, and doing it effectively is a band 7 requirement in its own right.
In Part 3 you can also simply ask: Could you explain what X means? The examiner is permitted to answer there. On the Part 2 cue card they are not, so paraphrase is your only route.
Band 6 against band 7
| Band 6 | Band 7 | |
|---|---|---|
| Range | Safe and generic — good, bad, important, very | Topic-specific words used where they fit |
| Precision | Meaning clear despite frequent odd choices | Awareness of style and collocation; slips occasional |
| Idiomatic | Rarely attempted, or memorised and forced | Natural phrasal verbs, unforced |
| Paraphrase | Generally successful, with some hesitation | Effective, without breaking the flow |
| Effort | Actively searching for words mid-sentence | Word choice mostly automatic |
The last row is the real difference. Band 7 vocabulary is not a bigger list — it is a list that arrives without being fetched.
How to actually build it
Collect from what you already say. Take the ten words you overuse — good, nice, a lot, thing, big — and find two precise replacements for each. That is twenty words that will definitely come up, which beats two hundred that might.
Learn pairs, not words. Heavy traffic, make progress, deeply concerned. Single words strand you at the moment you need the pairing.
Attach vocabulary to your stories. Three new words per prepared story arrive naturally, because the story pulls them.
Record yourself and listen for repeats. You cannot hear your own overuse in the moment. You hear it on playback immediately.
Say new words aloud before test day. A word you have only read will hesitate when you reach for it, and the hesitation costs more than the word gains.
Practise it
Record a two-minute answer, then transcribe the first minute by hand. Count how many times good, nice, very and a lot appear. That number, not your word list, is your current Lexical Resource ceiling.
You can practise IELTS Speaking with AI band feedback on IELTS Studio, which marks all four criteria separately so you can see which one is capping your band.
Related: Speaking topics covers the five stories worth preparing, Speaking Part 3 covers the abstract language the discussion needs, and how IELTS Speaking is scored explains all four criteria.
Frequently asked questions
- What does idiomatic vocabulary mean in IELTS Speaking?
- Mainly phrasal verbs used naturally — bring up, take over, switch off, chill out. It does not mean proverbs or sayings like raining cats and dogs, which sound rehearsed and rarely fit the question.
- What counts as less common vocabulary?
- Precise words rather than rare ones. Delighted instead of happy, a thriving city instead of a good city, a significant drawback instead of a bad thing. Precision, not obscurity.
- Do big words like plethora raise your IELTS Speaking score?
- No. Words such as plethora and amelioration are named as red flags because they usually appear in memorised phrasing and slightly wrong contexts, which lowers precision rather than raising range.
- What should I do if I forget a word during the Speaking test?
- Paraphrase it immediately and keep talking. Silence while you hunt for a word damages Fluency and Coherence more than the simpler word would have cost you.
- Are collocation mistakes penalised heavily?
- At bands 6 and 7 they are tolerated as long as meaning stays clear. By band 8 collocation needs to be accurate, with only occasional slips.
- How much topic vocabulary do I need for IELTS Speaking?
- Enough to discuss a subject specifically — sustainability or carbon footprint for the environment. But everyday vocabulary used precisely matters more than rare words used awkwardly.