How to Widen a Child's Vocabulary

Why teaching alone cannot do it

A school week has room to teach a few words properly — met several times, used in writing, checked later. Multiply that out and the year's total is a few hundred. The vocabulary needed to read a secondary textbook without stopping is many times larger than any timetable can hold, so this is not a scheduling problem a better plan would solve.

Most words therefore have to be picked up rather than taught, and they are picked up in text. Conversation runs on a small, repeating set of words even in a talkative household. Books are where a child first meets reluctant, consequently, diminish and hostile — ordinary in writing and rare in speech.

The words worth teaching on purpose

If only a few hundred words a year can be taught properly, which ones you choose matters more than how you teach them. The unhelpful choice is rare and impressive words. The useful choice is the middle band: too formal for conversation, common across every subject a child studies — analyse, factor, consistent, significant, sequence, derive, indicate, constrain.

Averil Coxhead's Academic Word List is the best available map of that band: 570 word families drawn from academic writing across arts, commerce, law and science, covering about 10 per cent of the running words in academic texts against about 1.4 per cent in fiction. That contrast is the point — these are the words school writing is made of and stories are not.

This explains a case that puzzles many parents. A child who reads enormous quantities of fiction and still struggles with a science textbook is meeting exactly this gap. Their reading is wide; it is simply not wide in that direction.

The roots that pay for themselves

A word family is not a set of spelling variations; it is a root and everything built on it. Teach spect, meaning to look, and a child has a route into inspect, spectator, spectacle, prospect, retrospect, perspective and suspect. One lesson buys seven words and, more usefully, a method for guessing the eighth.

A short list of roots does a disproportionate share of this work, and they are worth naming explicitly rather than hoping a child notices them.

Prefixes matter as much as roots, because they separate the members of a family: pre- before, re- again, ex- out, in- into or not, trans- across, con- with, sub- under. A child holding both halves can take apart a word they have never seen and land close enough to keep reading, which is the actual skill.

• spect — to look: inspect, spectator, perspective, retrospect
• port — to carry: transport, portable, export, deport
• dict — to say: predict, dictate, verdict, contradict
• struct — to build: construct, structure, instruct, destruction
• tract — to pull: extract, attract, contract, traction
• ject — to throw: reject, inject, projectile, trajectory
• scrib and script — to write: describe, prescription, manuscript, inscription
• mit and miss — to send: transmit, emission, permit, dismiss
• pos and pon — to place: deposit, component, compose, postpone

Keep reading aloud years after they can read alone

Most families stop reading aloud once the child can decode independently, which is several years too early. A child's listening vocabulary runs ahead of their reading vocabulary for a long time — they can follow a book well above the level they could manage alone — so a nightly read-aloud is the cheapest way to put harder words in front of them without making reading a chore.

It also supplies the two things a word needs to stick: a context and a voice. Stopping for ten seconds on grudgingly to say what it means costs nothing, and it is one of the encounters that word needs before it is the child's.

What to stop doing

Word lists learned for a Friday test and never seen again do very little, because a word met once in isolation has nothing to attach to. Words are held by the sentences they were met in. A word encountered in a story, discussed afterwards, then used in the child's own writing is a word that stays; the same word ticked off a list has gone by half term.

Word-of-the-day runs on the same principle and fails in the same way whenever the word does not come back. The fix is not more words. It is fewer words, met more often, in more places.

• Teach fewer words and bring each one back several times, in different sentences
• Explain a new word in a sentence the child could have said, not in dictionary language
• Ask for it in that week's writing, which is where it either sticks or does not
• Let the child read below their reading age for pleasure — fluent reading is where incidental learning happens; laborious reading is not