Speech and language: The 30 million word gap

In what has become iconic research, disadvantaged four-year-olds in the US were found to have heard 30 million fewer words than other children. This is a staggering and extraordinary idea. Researchers also identified a difference in the type and quality of interactions experienced by less well-off children with quality and quantity found to be of equal importance.

Although not without its critics - mainly around sample size and the estimates leading to the headline 30 million words conclusion - the research rightly focused our attention on what we all know - that early speech, language and communication deficits are powerful forces in holding children back, affecting their achievement and wellbeing into adulthood. This is something evidenced by a raft of similarly stark and convincing statistics published in the 25 years since the 30 million word gap study came out. These include research from the Institute of Education in 2006, which found the quality and quantity of children's vocabulary at age five is a strong predictor of how well they are doing aged 34. Meanwhile, nearly two thirds - 65 per cent - of young offenders have been found to have unidentified speech, language and communication needs.