Abstract
This thesis sought to achieve three key objectives. Firstly, it sought to develop and evaluate implicit-to-explicit continua for phonological and morphological awareness tasks. Next, it sought to develop our understanding of children with Developmental Language Disorder (DLD) by examining their profiles of strengths and weaknesses on these continua. Finally, it sought to develop our understanding of how having additional literacy difficulties, low IQ and/or English as an additional language (EAL) affect the profile of those with DLD.Recently there have been several papers that have noted that we do not know enough about precisely what our measures of phonological and morphological awareness are measuring (e.g., Duncan et al., 2013; Critten, Pine and Messer, 2013; Protopapas, 2014; Carroll and Breadmore, 2017). However, research has indicated that there may be implicit-to-explicit differences between task types, particularly for phonological awareness tasks (e.g., Roberts and McDougall, 2003; Gombert, 1992, Yopp, 1988; Ramus et al., 2013). This thesis further investigated this possibility by developing a phonological and morphological continuum for implicit-to-explicit task differences through the application of Karmiloff-Smith’s (1992) Representation Redescription Model’s framework and other task classification systems that are already present in the literature. These continua are then evaluated through a factor analysis study conducted with 81 typically developing children aged five years to twelve years old. The factor analysis indicated that both phonological and morphological tasks vary according to implicit-to-explicit task requirements.
The findings from the continua were then applied, allowing for a fine-grained evaluation of the profile of strengths and weaknesses of 70 children aged six years to eleven years old with DLD-only and compared them against individuals who are typically developing, DLD with literacy difficulties, DLD with low IQ and DLD with English as an Additional Language. Overall, these findings suggest that individuals with DLD have a profile of strengths and weaknesses for their phonological awareness in relation to their typically developing peers, but are much more wholly impaired in their morphological awareness than their phonological awareness abilities. However, the precise profile of difficulty varied considerably according to the diagnostic criteria used. Alongside the developments in our understanding of DLD, these findings have important implications for the support of those with DLD, as they can allow for more targetted interventions. These implications are especially important due to the new changes in the definition of DLD which now includes those children with broader difficulties (i.e., low IQ, reading difficulties or EAL). Furthermore, these findings suggest the importance of taking a fine-grained approach when investigating profiles of strengths or difficulties, as task selection could lead to large differences in results.
| Date of Award | Apr 2019 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Sarah Critten (Supervisor), Ian Mundy (Supervisor) & Julia Carroll (Supervisor) |