The acquisition of phonology in the first year of life
Any phonological theory needs to encompass an account of acquisition and any account of acquisition must take its place within a general theory of phonology. This thesis aims to ascribe phonological significance to speech perception in infancy, a move impossible unless phonology is defined, as it is here, from both a psycholinguistic and a formal viewpoint as a dedicated pattern-recognition system. Extant results from infant studies are reviewed and aligned with current phonological theory. In particular, such theory characterises phonology as bi-modular, so the acquisition of individual melodic and prosodic modules and their subsequent orientation with respect to one another must constitute three different developmental tasks. This delivers a relatively simple account of the mapping between psychoacoustics and phonology. Perception and pre-existing theories of segmental complexity are related using an original experiment into the perception of vowel-height contrast in Catalan. If infant perception has phonological import, then disparate phonetic reflexes which are predicted as phonologically identical should show parallels in acquisition. General theory argues that the same abstract melodic objects underlie both laryngeal contrasts in stops and lexical tonal contrasts. Earlier studies show that language-specific attunement to stop contrasts has taken place by the age of six months. New tests are now reported, using children of the same age, which demonstrate that infants acquiring Yorùbá, a language which has a three-way contrast for tone, attend more closely to pitch changes within the minimal domain word than do English controls. Further, they only attend to those pitch changes that possess phonological import within that domain in the steady-state language. In this their perception exactly parallels that displayed by adult speakers. Apparent anomalies in the results of these tests are shown to be closely parallelled by phonological asymmetries in the tonology of Yorùbá.