| Phonological development of Dutch children has been well documented in several studies. These studies have mainly been longitudinal and have looked at a small number of children (eg Fikkert 1994, Levelt 1994). Apart from qualitative studies, there has also been a study that has looked at larger group data (Beers 1992, 1995) and has applied a quantitative approach. In her dissertation, Beers compares the phonological development of 45 normally developing children [1;3-4;0] and 13 children with Specific Language Impairment. Beers used a cross-sectional design, in which she established the phonemic inventory of the two groups of children she looked at the application of phonological processes of the two groups of children. The current sub-project of Early language development in SLI and dyslexia: A prospective and comparative study latches on to the study of Beers. In our longitudinal and cross-sectional set-up, we will compare the phonological development of 70 normally developing children and 30 children with SLI. The current project is an extension not only in number of children included and in a variation of cross-sectional and longitudinal design, but also in selection of a third group of children whose phonological development will be taken into account. This group constitutes of 120 children who are at-risk for developing dyslexia. Thus, we will trace the phonological development of normally developing children and children at-risk for dyslexia from age 1;6-4;6, and the development of children with SLI from 3;0-4;6. Characteristic of the phonological development of children with SLI is that they display a development with protracted delay (Leonard 1998), in which the contrastive potential cannot be exploited for segmental development (Beers, 1995). Children with SLI further often display a restricted set of speech sounds, limited word and syllable shapes (Orsolini et al 2001, Pharr-Baird et al 2000) - especially consonant clusters (Gierut 1999, Chin and Dinnsen, 1992)- persistence of error patterns, chronological mismatch, unusual error types, and extensive variability, but lack of progress (Stoel-Gammon 1991, Grunwell 1991, Leonard 1998). Children with SLI are also prone to developing other language deficits, such as stuttering (Hall 1999) and dyslexia (Snowling et al 2001). Children with dyslexia have been noted to have had language difficulties before entering primary school. However, prospective studies which look at phonological development of children at-risk for dyslexia are scarce. Scarborough (1990, 1991) has conducted such a prospective study with children at-risk for dyslexia at age 2;0 and beyond. She found that early phonological production abilities were strongly predictive of reading status. The current project will also look at the phonological development of at-risk children before they can learn to read and write, commencing at age 1;6. Unlike many other conducted studies, the focus will be on children s phonological, not meta-phonological skills. We will compare the segmental- and syllable structure acquisition and the phonological processes applied by the three groups of children. Through this comparison we will try to address the question whether there is a common deficit in the phonological development of children at-risk for dyslexia and children with SLI (as suggested by eg. Mc Arthur et al 2000, Snowling et al 2000, Stothard et al 2000, Joanisse and Seidenberg 1998, Whitehurst et al 1991). This would mean that a number of children from the at-risk group will display the same type of phonological processes and follow the same paths of acquisition as children with SLI. Another part of the at-risk group is expected to tend more towards the acquisition as witnessed in normally developing children. Furthermore, by placing a special emphasis on complexity and length of target syllables, weak and strong syllable patterns, and distinctions between sounds differing predominantly in temporal cues, we will peek into the possibility the temporal processing deficit being the possible underlying cause of both SLI and dyslexia. Data will be elicited by using controlled object- and picture-naming tasks for the children aged 1;6-3;6. From age 4;0 onwards, meta-phonological tasks will also be presented to the children. At ages 1;6 and 3;6, the N-CDI, the Dutch version of the MacArthur CDI, will be filled in by the parents. We also hope to apply acoustic analysis to the data to trace possible differences of syllable planning of the groups of children. |
