Meaning and dyslexia : a study on pronouns, aspect, and quantification

Abstract

In this dissertation, I attempt at defining some properties of the cognitive deficit underlying dyslexia by looking at the ability of dyslexic subjects to comprehend language. Dyslexia is a language-based learning disability, defined as a failure to learn to read properly despite normal intelligence, normal hearing, adequate classroom exposure, and absence of physical, emotional and socioeconomic problems. There is wide consensus that dyslexia is caused by difficulties related to the processing of phonological representations. There is also experimental evidence that dyslexic subjects experience difficulties in the comprehension of certain aspects of language, among which tough-sentences (such as ‘the bird is tasty to bite’), object extracted relative clauses, pronouns in Condition B configurations cross-sentential anaphora, and scalar implicatures. In this dissertation, I provide further experimental evidence that dyslexic subjects experience comprehension difficulties. In particular, dyslexic subjects are shown to differ significantly from their unimpaired peers in the comprehension of sentences containing a pronoun ambiguous between a bound and a coreferential reading, imperfective aspect, and universally quantified noun phrases in quantifier spreading contexts. To account for the data, I propose that dyslexia is associated with a verbal working memory deficit, where the term ‘verbal working memory refers to the component of the Working Memory system that is responsible for the temporary storage of verbal information, when required in order to perform further linguistic computations. The proposal accounts bith for the reading difficulties and the language comprehension difficulties. It also accounts for the fact that the language related difficulties experienced by dyslexic subjects are mostly found in those domains of language that are also problematic for preschool children. The results achieved provide support for a type of linguistic theorizing that stresses the interdependence between linguistic computations and processing resources. In particular, I promote a type of research whose goal is to adequately describe linguistic computations as implemented in a resource-limited system. This line of research has significant implications for deciding between competing linguistic theories, individuating the cognitive engines that support linguistic computations, and defining the cognitive profile of subjects with a language impairment