Young children’s verbal interactions with adults have a bigger impact on their language development than the number of words they hear, academics have found.

New research suggests that the number of times children aged 18 to 24 months are engaged in a back-and-forth exchange with an adult, so called “conversational turns”, is related to their verbal skills as they grow up.

The findings come from research which analysed 12-hour-long audio recordings of young children, and then tested their language skills around a decade later.

It showed that the number conversational turns a child takes in the “relatively narrow developmental window of 18 to 24 months of age” can be used to predict school-age language ability.

The authors of the research, which was carried out in the United States, say it shows the importance of effective early intervention programmes to support language learning at home.

The research used software which analysed recordings of the 329 young children to work out how many conversational turns they took during the day.

Around 150 of these children then took part in later tests to analyse their verbal comprehension.

Early years: closing the disadvantage gap

The research looked at three age groups: 2 to 17 months, 18 to 24 months, and over 25 months.

It found a link between both conversational turns and adult word count for children between the ages of 18 to 24 months and these pupils’ ability later on at school age - but said that the link was stronger for conversational turns.

The academics said that no significant relationship was found for younger or older children outside the 18- to 24-month group.

The findings are outlined in a paper by Jill Gilkerson, Jeffrey A Richards, Steven F Warren, D Kimbrough Oller, Rosemary Russo, Betty Vohr, published in Pediatrics, the journal of the American Academy of Pediatrics.

The UK government has made boosting young children’s vocabulary a major priority in its social mobility action plan, published 12 months ago under former education secretary Justine Greening.

It warned that by the age of three, disadvantaged children are - on average - already almost a full year and a half behind their more affluent peers in their early language development.

The Department for Education has also backed a new trial which will send parents of young children in disadvantaged communities text messages to prompt them to teach new words and numbers.

The trial in the North of England, led by the Education Endowment Foundation and SHINE Trust, is part of a raft of government-backed measures to improve young children’s early communication skills.