Early phonology and grammar of children with developmental language disorder

Children with a developmental language disorder (DLD) have severe language learning difficulties that do not have a clear cause. These children form a heterogeneous population regarding the severity of their deficits as well as the affected language domains. Despite this heterogeneity, many children with DLD have difficulties with grammar and speech sound production. In the Netherlands, children with severe DLD can attend specialized language intervention groups or special education schools. In these language programs, children’s language development is monitored frequently in order to evaluate treatment effects and select appropriate treatment goals. To track children’s development, clinicians need outcome measures that can capture (subtle) growth over short periods of time. This dissertation provides detailed overviews of the phonological and grammatical development of three- to six-year-old children with DLD. These overviews are used to design new outcome measures, which are in turn used to examine the association between phonological and grammatical development. The results show that young children with DLD do improve in their phonological and grammatical development over a period of nine months. The strength of the relation between phonology and grammar decreases over time, indicating that the developmental trajectories in these domains are dynamic and not continuously related. These insights can help clinicians in designing interventions targeting phonology and/or grammar in different phases of language development. This dissertation also underlines the importance of combining different types of measures (for instance, the use of sentence structures in combination with the correctness of these structures) in monitoring children’s grammatical and phonological development. Including different types of measures provides a broader perspective on the relative strengths and challenges of individual children with DLD. This approach can lead to more effective, tailored interventions that address the specific phonological and grammatical needs of each child.