How to read the evidence
Some of what follows is statutory guidance schools must follow, some is a synthesis of research, and some is widely recommended practice that has not been separately trialled. We have tried to say which is which. The EEF rates oral language approaches — explicit vocabulary teaching among them — as high impact for very low cost on extensive evidence, but it has not published separate effect sizes for individual techniques such as word walls or knowledge organisers. And an average effect across many studies is not a promise about any one child.
About the "word gap"
You will meet the claim that children from poorer homes hear 30 million fewer words. It comes from a small American study from 1995, and a 2019 replication attempt in Child Development did not reproduce it. Vocabulary at school entry does vary, and that variation does predict later attainment — but the causes are complex, and framing it as a family failing is both unkind and unsupported. Teach vocabulary because it is teachable, not because anyone is deficient.
Department for EducationProfessional guidance
The reading framework: teaching the foundations of literacy (2021, updated 2023)Sets out the Simple View of Reading — comprehension depends on word reading and language comprehension together — and a substantial section on developing talk. It is about teaching practice, not about any particular vocabulary programme.
Department for EducationStatutory guidance
SEND Code of Practice: 0 to 25 years (2015)Names communication and interaction as one of the four broad areas of SEN and sets out the graduated approach — assess, plan, do, review — that schools must follow.
Department for EducationStatutory guidance
Early years foundation stage statutory framework (current version)Communication and language is one of three prime areas; providers must give children a language-rich environment and back-and-forth conversation.
Education Endowment FoundationResearch summary
Oral language interventions (Teaching and Learning Toolkit)Rates oral language approaches — including explicit vocabulary teaching and structured discussion — as high impact for very low cost, based on extensive evidence. The Toolkit is revised periodically; check the live page for the current figure rather than quoting an older one.
Education Endowment FoundationResearch summary
Preparing for Literacy: improving communication, language and literacy in the early years (2018)Recommends high-quality adult–child interaction and deliberate vocabulary development, and notes the recommendations may also apply to older pupils who have fallen behind.
Education Endowment FoundationResearch summary
Improving Literacy in Key Stage 1 (2017, updated)Places language capability — vocabulary, listening and structured talk — among the foundations of early reading and writing.
Education Endowment FoundationResearch summary
Improving Literacy in Key Stage 2 (2017, updated 2021)Recommends teaching a small number of useful words in depth, teaching pupils how words work — including roots, prefixes and suffixes — and using structured discussion to build comprehension.
Education Endowment FoundationResearch summary
Getting to the root of vocabulary instruction (blog) (2024)Discusses morphology — teaching how words are built — as a promising approach. Promising is the right word: the UK trial base here is still small.
Royal College of Speech and Language TherapistsProfessional guidance
Clinical information: developmental language disorder (DLD)Reports that DLD affects around 7.6% of children — roughly two in a class of thirty. DLD affects understanding and using language and is diagnosed by a speech and language therapist, not inferred from a low vocabulary score.
NICEProfessional guidance
Early years: promoting health and wellbeing in under 5s (QS128), quality statement 2: speech and language (2016)Notes that children with communication difficulties are at increased risk of social, emotional and behavioural difficulties. It concerns early identification in the under-fives, not primary-age vocabulary teaching.
Clegg, Law, Rush, Peters & RoulstoneResearch evidence
The contribution of early language development to children's emotional and behavioural functioning at 6 years (ALSPAC), Journal of Child Psychology and Psychiatry (2015)UK birth-cohort study finding an association between early language and later emotional and behavioural functioning. Observational, so it shows a link, not that improving vocabulary improves behaviour.
Dixon, Thomson & FrickeResearch evidence
Evaluation of an explicit vocabulary teaching intervention for children learning English as an additional language in primary school, Child Language Teaching and Therapy (2020)UK primary evaluation showing explicit vocabulary teaching benefits pupils learning English as an additional language.
Murphy & Unthiah (University of Oxford, for the EEF and the Bell Foundation)Research summary
A systematic review of intervention research examining English language and literacy development in children with EAL (2015)Review of what helps pupils learning EAL. A lower score on an English-only vocabulary test is a measure of English exposure, not of ability or of a language disorder.
CushingResearch evidence
Word rich or word poor? Deficit discourses, raciolinguistic ideologies and the resurgence of the 'word gap' in England's education policy, Critical Inquiry in Language Studies (2022)A UK critique of how the 'word gap' has been used in English education policy. Worth reading alongside the vocabulary literature, not instead of it.
Sperry, Sperry & MillerResearch evidence
Reexamining the verbal environments of children from different socioeconomic backgrounds, Child Development (2019)Found that the widely quoted '30 million word gap' figure (Hart & Risley, 1995, USA) does not replicate. The figure is still repeated in training materials; it should not be treated as established fact.
Speech and Language UKProfessional guidance
Ages and StagesQualitative descriptions of typical communication development by age band. Ranges, not norms — individual variation is expected.
NHSProfessional guidance
Help your child learn to talkPlain-language NHS advice for families on everyday talk. Practical guidance rather than a research source.
