Closing the word gap

What contributes to the variation in children’s language development in the early years?

By Padraic Monaghan, Professor of Cognition in the Department of Psychology at Lancaster University, co-director of the ESRC International Centre for Language and Communicative Development (LuCiD), and a Research Associate at the Max Planck Institute for Psycholinguistics.

Language and literacy skills have a huge impact on a child’s life outcomes. Recent research has shown that there is a significant gap between children with good and poor language skills when they begin school and that this gap remains consistent throughout their schooling. It is therefore absolutely vital that language skills prior to school are promoted to address this gap.

So, what contributes to this variation in children’s language development in the early years? One key factor is how much language children hear during their early development. It is well-documented that the number of words children hear in the first five years of their life is linked to the size of their vocabulary at age five. This relation between the quantity of language heard and the size of a child’s vocabulary is not at all surprising, as we know that in order to acquire a word early in a child’s development, they first need to hear the word. We also know that repetition is key: the more times a child hears a word the more likely they are to learn it.

But it is not only the quantity of words that matters. Also of critical importance is the variety of the language that children experience. It is often difficult to distinguish quantity from variety, because they are closely related: the more words the child experiences, the more likely they are to hear some of the rarer words in the language. However, studies of child-directed speech have carefully teased these contributions apart, and shown both to be predictors of children’s language development.

Recent developments in our understanding of word learning have enabled us to draw direct links between the quantity and variety of language and vocabulary development. These studies use computer models of what we know about how children acquire words to determine how the language they hear affects their language learning. In a ground-breaking study, Gary Jones and Caroline Rowland demonstrated that when the child knows more words, this helps them to group together combinations of speech sounds, which in turn makes it easier to learn a new word comprising speech sounds that the child already knows. Crucially, they showed that, as the child develops, it is the diversity of the vocabulary they hear that becomes more effective than the quantity in boosting their vocabulary size and influencing how easily new words can be learned.


Building on this work, at LuCiD we have shown how early knowledge about sounds and meanings of words affects how we learn to read. Again, using computer models of language acquisition and literacy development, we have demonstrated that the quantity of language a child experiences before learning to read has a substantial and long-term effect on their ability to learn to read. In addition, learning to read is also made easier by the variety of words a child has heard. This is because learning to read piggy-backs on oral vocabulary: it is much easier to read a word for which a child already knows the sound and meaning, because then the sounds and meanings don’t have to be learned at the very same time that a child is also acquiring their letter knowledge.

What, then, are the practical implications of these studies? First of all, they confirm that greater language experience improves language skills, so programmes that promote care-givers talking to their children are extremely important and beneficial. But these studies also highlight the importance of variety in language, and so promoting diverse vocabulary use will also help.

Fortunately, many aides aimed at increasing language exposure are also likely to promote diversity. For instance, shared book reading expands vocabulary exposure because books tend to contain a wider vocabulary than spoken language. Or talking about events in the past or future introduces words that are not so relevant to the present. Awareness of the importance of both quantity and quality will have positive benefits on early language skills, literacy development, enabling us to narrow the language gap.


Padraic will be presenting his research on the effect of quantity and diversity of early language on vocabulary development and later effects on literacy at the National Literacy Trust’s annual Talk to Your Baby conference in London on 19 March 2018.

For 15 years, Talk To Your Baby has brought together the leading experts in early language and communication development to share the latest research, practice and policy with early years professionals in the UK. Book your place at Talk To Your Baby 2018 by visiting https://literacytrust.org.uk/ttyb, emailing conferences@literacytrust.org.uk or calling 020 7820 6258.