Study title

United Kingdom

Individual

The initial cohort of children participating in the Manchester Language Study was a random 50% sample of all Year 2 children attending mainstream language units in England. Of the 242 identified and recruited at Year 2 (on average, 7 years of age), 139 young people (57.4% of the original cohort) agreed to participate at age 16, 69.8% were males and 30.2% were females, ranging in age between 15;2 and 16;10. The attrition observed was partly due to funding constraints at follow-up stages of the study. Of those who did not take part, contact had been lost with 51 individuals (21.1%) and 52 children (21.5%) did not consent to take part.A comparison group of 124 typically developing (TD) adolescents from a broad background participated in the Manchester Language Study at approximately age 16, 59% were males and 41% were females, ranging in age between 15;2 and 16;7 years). At this wave of the study, data as per the 2001–2002 General Household Survey (Office for National Statistics, 2001–2002) were consulted to target adolescents who would be representative of the range and distribution of households in England in terms of household income and maternal education. Initially, TD adolescents from the same schools as the participating adolescents with SLI were targeted. This was followed by a second wave targeting schools in areas where more representation in terms of particular household income/maternal education brackets was required. The TD adolescents had no history of special education needs or speech and language therapy provision and thus did not have reports of conditions that may have affected their learning, such as attention deficit hyperactivity disorder, autism spectrum disorder, or other behavioural difficulties.At the time of this phase of the MLS, all adolescents (DLD and age-matched peers) were attending the last year of compulsory secondary education.Following informed written consent from families, children were visited at school and given self-report questionnaires, individually, in a quiet room or area. The structured interviews were carried out in a conversational style following the young people’s pace and encouraging them to fully communicate their responses. Care was taken to ensure that all participants comprehended the questions and the interviewers were able to provide additional clarification, rephrasing, and/or repetition of the target and probe questions as often as necessary. A battery of psycholinguistic tests was also completed as part of this phase of the study, for the DLD participants who had no psychometric data collected at age 14 and for all the age-matched peers. The young people with DLD and their age-matched peers were assessed individually at school by a researcher and interviewed/tested in a quiet room or area. The teachers’ interviews were carried out separately, in school. The parents of the young people were interviewed separately at home for single period of about 2 hours.