Cambridge Insight Blog

We need to talk about: explicitly teaching vocabulary

Written by Cambridge Insight | May 20, 2026 8:34:01 AM

Why is vocabulary fundamental to student progression in all subjects? How can a coordinated, whole-school approach strengthen vocabulary acquisition for all learners?

What percentage of words do you think a reader needs to know before they can understand a text? Would 70 or 80% be enough for them to get the gist?

Let’s start at 80%. How accessible is the following text for you?

“Bingle for help!” you shout. “This loopity is dying!” You put your fingers on her neck. Nothing. Her flid is not weafling.

You take out your joople and bingle 119, the emergency number in Japan. There’s no answer!

Then you muchy that you have a new befourn assengle. It’s from your gutring, Evie. She hunwres at Tokyo University. You play the assengle.

“… if you get this…” Evie says “… I can’t vickarn now… the important passit is…” Suddenly she looks around, dingle. “Oh no, they’re here! Cripett… the frib! Wasple them ON THE FRIB!...”

BEEP! The assengle parantles. Then you gratoon something behind you…

Excerpts taken from Extensive Reading Benefits and Implementation. Benevides Marcos J.F. Oberlin University, Tokyo, Presented at IATEFL 2015 in Manchester

For those of us with strong reading skills, the multiple nonsense words here will pose frequent distractions, but we are likely to be able to get a rough gist of what is happening. The same might be said of any learner we put this kind of text in front of: they may get ‘the gist’.

But what happens when you start posing your retrieval questions? What is the ‘flid’ and why isn’t it ‘weafling’?

Research says that for a learner to independently read and comprehend a text, they must know 98% of the words used: no more than 2 in 100 words should be unknown (Carver, 1994). Beyond this, the text becomes difficult to understand without support.

It is generally accepted that by the end of secondary school, most children will have a working vocabulary made up of around 20,000+ words. However, research also tells us that learners reach secondary school with widely varying vocabulary sizes (Biemiller, 2003), and that these differences tend to persist throughout school if they are not specifically addressed.

Download the guide below for some tips on how to teach vocabulary and reading in secondary schools to maximise comprehension.

Get the guide now

References

  • Biemiller, A. (2003). Vocabulary: Needed if more children are to read well. Reading Psychology, 24(3-4), 323–335.
  • Carver, R. P. (1994). Percentage of Unknown Vocabulary Words in Text as a Function of the Relative Difficulty of the text: Implications for Instruction. Journal of Reading Behavior, 26(4), 413-437.