Robin van Rijthoven

11 General introduction 1 To overcome reading and spelling problems, children with dyslexia need interventions to build strong and bi-directional phonology-orthography connections. However, most interventions thus far focused primarily on reading (see Galuschka, 2014) and thus only stimulate the orthography-phonology connections instead of stimulating the bidirectional relationship via combining both reading and spelling. As a case in point, prior research showed that spelling development benefits reading development as well (see Ehri & Wilce, 1987) and so more focus on orthographic learning could compensate for phonological shortcomings. The response to a so-called phonics through spelling intervention, aiming to enhance the bi-directional relationships between phonology and orthography, has not yet been studied and could give more insight in the benefits of adding a solid amount of spelling to an intervention for children with dyslexia. Furthermore, it is important to gain insight in relative strengths and weakness, profiles and its relation to intervention outcomes in order to optimize the (choice of) interventions and to build upon strengths to overcome difficulties (see Protopapas, 2019). In line with the reasoning above, the focus of this dissertation was to examine two sources of compensation for the phonological shortcomings underlying the reading and spelling problems of children with dyslexia: (i) enhancing semantic representations and (ii) enhancing orthographic representations bymeans of a phonics through spelling intervention. Dyslexia Learning to read and spell According to the lexical quality hypothesis (Perfetti, 2007), becoming a proficient reader or speller requires high-quality lexical representations. According to the triangular framework, phonological, orthographic, and semantic representations are built throughout literacy development, which together form an efficient and recurrent network that is necessary to read and spell efficiently (Seidenberg & McClelland, 1989). Wordswithmorehigh-qualityphonological, orthographic and semantic representations are easier to read and spell than words with lower lexical quality (Perfetti, 2007; Perfetti et al., 2005). According to the lexical quality hypothesis word representations can be characterized by two dimensions: specificity and redundancy. Lexical specificity refers to the degree to which words are specified phonologically, semantically, and orthographically. Redundancy refers to the extent that lexical representations can be retrieved from memory; lexically and/or sublexically (Perfetti, 2007). Already at young age, the foundation of literacy is laid, as children start to develop their spoken language. Children learn large numbers of words (phonological representations) and their meanings (semantic representations). By learning these words phonological and semantic representations are connected (Levelt, 1989; Levelt et al., 1999). Reading