The development of phonological representations remains a hot topic within both the developmental and neural network literature. Historically, theoretical accounts have fallen within one of two camps: the accessibility account which proposes that phonological representations are adult-like from infancy (Rozin & Gleitman, 1977; Liberman, Shankweiler & Liberman, 1989) and the emergent account which proposes that phonological representations become gradually restructured over development (Metsala & Walley, 1998; Ventura, Kolinsky, Fernandes, Querido & Morais, 2007; Ziegler & Goswami, 2005). Within this thesis we tested predictions made by the accessibility account and key variants of the emergent account using data from both behavioural (Chapters 2, 3 and 4) and neural network studies (Chapter 5). The novel measures used within Chapters 2 to 4 were devised to allow us to contrast implicit measures of phonological representation (PR) which probe the segmentedness of the representations themselves, with explicit PR measures which tap into children’s conscious awareness of phonological segments. Within Chapter 2 we present evidence that while explicit awareness of phonological structure is dependent on letter-sound knowledge, implicit sensitivity to the segments within words emerges independent of literacy. Within Chapter 3 a longitudinal study investigated the segmentedness of children’s phonological representations at the rime and phoneme level. These results demonstrate that implicit sensitivity to both rime and phoneme segments is driven by vocabulary growth and is not dependent on letter-sound knowledge. The results within Chapter 3 also suggest that, while awareness of rime segments emerges naturally through oral language experience, explicit awareness of individual phonemes is related to letter-sound knowledge. In Chapter 4 we explored the idea of global versus phonemic representation using a mispronunciation reconstruction task. We found that sensitivity to both global and phonemic similarity increased over time, but with global sensitivity reaching adult levels early on in development. In Chapter 5 a neural network was trained on the mappings between real acoustic input and articulatory output data allowing us to simulate the development of phonological representations computationally. The simulation data provide further evidence of a developmental increase in sensitivity to both global and phonemic similarity within a preliterate model. Taken together, the results provide strong evidence that as children’s vocabularies grow they become increasingly sensitive to both the global properties and segmental structure of words, independent of literacy experience. Children’s explicit awareness of phonemes, on the other hand, seems to emerge as a consequence of learning the correspondence between letters and sounds. Within the context of the wider literature, the current results are most consistent with the PRIMIR framework which predicts early detailed phonetic representations alongside gradually emerging phonemic categories (Werker & Curtin, 2005). This thesis underlines the importance of using implicit measures when trying to probe the representations themselves rather than children’s conscious awareness of them. The thesis also represents an important step towards modelling the emergence of segmental representation computationally using real speech data.

Cette thèse est une investigation de la structure syntaxique et de l'interprétation modale des phrases impliquant le modal dénominal de nécessité behar ‘devoir, falloir, avoir besoin’ et un complément infinitif. La thèse analyse le statut syntaxique des compléments non finis du verbe modal denominal behar en examinant leur interaction avec des phénomènes syntaxiques sensibles à des conditions structurelles et de localité diverses, et conclut que les compléments d’infinitif de behar peuvent correspondre à différentes structures sous-jacentes. Le type d'infinitif le plus complexe du point de vue structurel est un infinitif non-restructurant qui projette une architecture de phrase complète (c.-à-d. une CP), et le plus petit est un infinitif réduit de restructuration qui projette une structure de phrase de niveau vP. Il y a des preuves pour l'existence des types intermédiaires projetant jusqu'au domaine flexionnel (IP / TP). D'autre part, la thèse examine les propriétés thématiques et de portée des sujets dans chacun des différents types structurels et l'interprétation modale à laquelle elles donnent cours. Sur la base de cette analyse, la thèse soutient que l'interprétation modale n'est déterminée par aucun facteur en particulier (la présence de la restructuration, le statut référentiel du sujet et sa portée relative vis-à-vis du prédicat modal, parmi d'autres fréquemment mentionnés), mais dépend de l'effet cumulatif de plusieurs facteurs travaillant ensemble. La thèse montre également la nécessité d'adopter une vision plus fine de la modalité radicale (root modality), qui permet une association plus simple entre structures syntaxiques et significations modales. / This dissertation is an investigation of the syntactic structure and modal interpretation of clauses involving the denominal necessity predicate behar ‘need’ and an infinitival complement. On the one hand, it analyses the syntactic status of non-finite complements of denominal behar by examining their interaction with syntactic phenomena sensitive to different structural and locality conditions, and concludes that the infinitival complements of behar can correspond to different underlying structures. The largest type of infinitive is a non-restructuring infinitive that projects a full clausal architecture (i.e. a CP), and the smallest one is a reduced restructuring infinitive that projects up to vP. There is evidence for intermediate types projecting up to the inflectional domain (IP/TP). On the other hand, the dissertation examines the thematic and scope properties of the subjects in each of the different structural types and the modal interpretation that they can give rise to. On the basis of this analysis it is argued that modal interpretation is not constrained by any single factor (the presence of restructuring, the referential status of the subject and its relative scope vis-à-vis the modal predicate, among other frequently mentioned ones), but depends on the cumulative effect of several factors working together. The dissertation also shows the necessity of adopting a more fine-grained view of root modality, one that allows a simpler mapping of syntactic structures into modal meanings.