Étude des connaissances morphologiques dérivationnelles en modalité orale et en modalité écrite d'élèves dyslexiques du primaire

Reading is at the heart of school learning and likewise, at the heart of success in many school subjects. However, not all learners develop this skill with ease. In fact, some students will experience reading difficulties throughout their school years. It is particularly the case of students with dyslexia, a reading disability. Dyslexia would be associated to a phonological deficit which would hinder, in the learners that are affected, the achievement of graphemes-phonemes correspondences during word recognition. Since this is said to be specific to reading and strongly linked to text comprehension, dyslexic students experience significant difficulties to read. Word recognition involves the activation and use of various types of knowledge linked to phonological, morphological and visuo-orthographic properties of written words. This knowledge and the procedures which are associated to them are established during the first years of schooling for students whose reading development is typical. They enable them to create orthographic representations corresponding more and more to the standard. The quality of these representations stored in memory contribute to success in word recognition. However, for dyslexic students, word representations often lack precision, which leads to errors during reading. Since phonological knowledge and procedures are generally said to be deficient in dyslexic students, researchers have been trying for several years to identify other procedures that could be useful to them. For this reason, these researchers are interested in the morphological knowledge of dyslexic students during reading. Consequently, since words have some properties that are non-phonological, in particular morphological properties, it is possible to consider that these students use these other properties to recognize words. The current review of the scientific literature on this question does not provide a clear picture of the situation. A reason that could account for this observation concerns the great variability of the tasks selected in the different studies and the fact that some tasks were performed in oral modality and others, in written modality. These tasks also vary in terms of cognitive constraints. It is thus not surprising that they are associated with varying success rates. Furthermore, since oral knowledge is the first to develop and that it generally serves as the basis on which written knowledge is built, it is possible to think that those administered orally will have a better success rate than written tasks. However, studies have not attempted to hierarchize tasks to better understand the results of work carried out in the field and thus account for the potential role of morphological knowledge in reading. They also have not considered the modality in which the tasks are administered (oral or written). In this study, our objective is thus to assess et compare morphological knowledge, in oral and written modalities, of elementary school dyslexic students by using different tasks that are hierarchized from the start. The performances of these students were compared with those of two groups of normal readers: younger students, but with the same reading level as the dyslexic students (RC) and same age students (AC), in order to better understand reading behaviors of dyslexic students. To assess reading abilities, a word recognition test from the WIAT-II test battery, a reading comprehension test from the K-ABC test battery and a vocabulary test (EVIP) were used. For the evaluation of morphological knowledge, three tasks (morphological relation judgment, decomposition and plausibility judgment) with different cognitive constraints were selected following a literature review. These tasks were administered to all participants first orally then, several days later, in writing. The results from the analysis of variance conducted reveal that dyslexic students obtain success rates generally comparable to RC in morphological tasks. This corroborates the results of other studies and meets our expectations. However, for certain tasks, they are not significantly different from AC, which could indicate that the morphological knowledge of dyslexic students is more elaborate than what we have anticipated in relation to their reading abilities. We also observed an effect of the cognitive constraints attached to each of the morphological tasks. Furthermore, an effect of the task administration modality was observed, but only for the plausibility judgment task and only for dyslexic students. Hence, in general, contrary to our expectations, the modality does not seem to have had an impact on the performances of AC and RC groups. These results have theoretical and practical consequences which are discussed at the end of this thesis.

Keyphrases: derivational morphology, word recognition, reading, reading disability, dyslexia, elementary school, French