Developmental Language Disorder and Language Impairment

Children with developmental language disorder (DLD; also referred to as specific language impairment) experience a significant deficit in language ability that is longstanding and harmful to the children's academic, social, and eventual economic well-being. Word learning is one of the principal weaknesses in these children. This project focuses on the word learning abilities of four- and five-year-old children with DLD. The goal of the project is to build on the investigators' previous work to determine whether, as has been found thus far, special benefits accrue when these children must frequently recall newly introduced words during the course of learning. In this study, the investigators seek to replicate the advantage that repeated retrieval holds over simple exposure to the words appearing in the context of a story book by increasing the degree to which the words are integrated into the story line.

The overall aim of this clinical trial is to evaluate an at scale version of 'Happy Talk' in a large scale effectiveness study (examining inputs, outputs and outcomes) based on a sample of children from socially disadvantaged areas. Researchers will compare Happy Talk to usual care and children's allocation to the programme will be decided on randomly. The investigators also aim to * complete a pre-trial process evaluation to inform intervention implementation - examining factors which promote parental engagement and partnership between SLTs and educators and incorporating these into SLT training and future rollouts of the programme. * complete a concurrent process evaluation from a realist perspective to examine how the mechanisms underpinning Happy Talk are influenced by the implementation context and therefore what would need to be considered for successful implementation across varied settings. Our SWAT is embedded in this process evaluation and addresses the Trials Methodology Research Network methodological priority questions 1 and 5 https://priorityresearch.ie/priority-one-questions/ * Complete an economic evaluation in which compare the costs and benefits of Happy Talk are compared to standard pre/school care. The study aims to answer the following research questions: When implemented at scale 1. Does 'Happy Talk', a targeted selective intervention focused on increasing parent and early educator responsive interaction, improve language and quality of-life (QoL) outcomes in socially disadvantaged preschool and young school-aged children? 2. Does Happy Talk enhance responsiveness and language promoting behaviours in home and pre/school contexts? 3. What programme features support successful real-world application of 'Happy Talk' including factors which promote parental engagement; partnership between SLTs and educators; and fidelity of implementation? 4. How do contextual factors influence Happy Talk implementation /outcomes? 5. How can trials become part of routine care? 6. Is Happy Talk cost effective compared to usual care? Intervention: The programme is informed by general systems theory and is embedded in the preschools, and homes of socially disadvantaged children with the aim of effecting change in parent and educator behaviour. There are both parent and preschool staff components to the programme.