Vocabulary & Word Knowledge
What it means to really know a word, why word knowledge sits underneath so much classroom learning, and how adults can build it deliberately without turning language into a deficit.
Vocabulary is the words a child knows; word knowledge is how well they know them — what a word means, when you would use it, how it changes and what it sounds like. Depth matters more than the count. Most children understand far more words than they use, and a word usually has to be met several times, in different situations, before it becomes theirs. It matters because understanding what you read or hear depends on knowing the language it is made of, which is why a child can read a page perfectly and still not follow it. But vocabulary is not intelligence, and a smaller English vocabulary often means less English so far rather than less capability — especially for children growing up with more than one language.
Everyday things you may see
These are observations, not labels. One on its own means very little; a pattern over time is worth talking about.
- Reaches for "thing" or "stuff" instead of the word they want.
- Reads accurately but cannot say what the text was about.
- Understands a word one week and it has gone the next.
- Gets maths word problems wrong while the calculations are right.
- Uses a nearly-right word — "the bit that goes round" for wheel.
- Avoids books or conversations pitched slightly above them.
- Talks at length about a favourite subject and briefly about everything else.
Supporting your child at home
Small, achievable things that make a real difference — no special resources needed.
- Say the grown-up word too
"It's soaking — absolutely drenched." Children pick words up from hearing them used, not defined.
- Meet a word three times
Notice one interesting word today, use it again tomorrow and later in the week. The repetition is what makes it stick.
- Keep reading to them
Reading books harder than they could manage alone is one of the most reliable ways to meet new words.
- Ask what they think
"Why do you think he did that?" invites far more language than "what colour was the door?"
- Let them be the expert
Ask them to explain something they love. Long talk about a familiar subject uses more vocabulary than answering questions about an unfamiliar one.
Five evidence-informed ideas
Practical, realistic and usable in a mainstream classroom tomorrow.
- Choose fewer words, teach them properly
Two or three high-value words per unit, revisited across weeks, beats a list of twelve met once.
- Pre-teach before the text
Three minutes on the words that would otherwise block a reading, with a picture or concrete example rather than a definition to copy.
- Define by use, not dictionary
"Fragile means it breaks easily — an egg is fragile, a football is not." Two contrasting examples do more than a definition.
- Require the word back
Expect taught vocabulary in spoken and written answers. Use, not exposure, is what fixes a word.
- Read aloud above their reading level
Books carry words that conversation does not, and listening removes the decoding cost — worth protecting right through Year 6.
What is often assumed — and what the evidence says
Reading words accurately and understanding them are separate. A fluent reader can decode a page of unfamiliar words and take nothing from it.
It does — for children who already know enough words to work out new ones. Below that point, explicit teaching is what helps.
They have less English so far. UK research finds English vocabulary grows quickly with exposure, and vocabulary across all their languages is often comparable to peers'.
That figure comes from a small 1995 US study and did not replicate when retested in 2019. Vocabulary does vary at school entry; the deficit story attached to it is contested.
Share what you notice — words that don't stick, misread questions — and ask whether school sees the same pattern.
If words are being explicitly taught and revisited and still are not being retained or used, ask the SENDCO to review the wider language picture.
Where difficulty with words sits alongside difficulty understanding or building sentences and is persistent, school may suggest speech and language therapy. A hearing check is worth doing too.
A low vocabulary score is not a diagnosis. Only a speech and language therapist can diagnose developmental language disorder.
Go deeper when you want to
The complete professional guide to vocabulary & word knowledge — research, classroom practice and implementation.
OpenSearch the strategy library for immediate, practical classroom ideas.
OpenPlain-English guides, scripts and printable tools for families.
OpenThe mental notepad that lets a child hold information in mind long enough to use it — and the small changes that make the biggest difference.
Planning, flexibility and impulse control — the mental machinery that lets a developing brain get things done.
What we mean by attention, why it wanders, and the classroom conditions that help it hold.