The Role of Cognitive Ability in the Acquisition of Second Language Perceptual Phonological Competence

[eng] Many second language (L2) learners find L2 pronunciation difficult and experience perception and production problems leading to accented speech. There exists a great inter-learner variation in L2 phonological acquisition even among learners who have been exposed to the L2 since childhood. Such individual differences have been the focus of much second language acquisition (SLA) research. Relatively little attention has been paid to the role of learners' cognitive ability in the acquisition of L2 perceptual phonological competence. This dissertation seeks to fill this gap by addressing the following question: To what extent does cognitive ability contribute to learners' acquisition of L2 sounds? We hypothesized that phonological short-term memory, acoustic short- term memory and attention control facilitate L2 learners' acquisition of perceptual phonological competence. A group of 45 adult Catalan-Spanish bilingual learners of English were asked to participate in a battery of L2 perception tests measuring their L2 vowel perception and cognitive tests assessing their attention control ability and short-term memory capacity for speech sounds. The target L2 sounds were those comprised in the English vowel contrasts /i/-/? /, /? /-/? /, /? /-/? /, /? /-/ae/ and /? /-/ae/. The learners' ability to perceive a cross-language phonetic distance between these L2 vowels and those in their native language (L1) and their success in establishing new phonetic categories for L2 vowels were assessed by means of a perceptual assimilation task and a categorical vowel discrimination task, respectively. The contribution of phonological short-term memory, acoustic short-term memory and attention control was examined by relating the outcome measures of cognitive tests to those of learners' L2 vowel perception. Overall, the results obtained partly confirmed the hypothesis. Short-term memory capacity for phonological and acoustic information and attention control ability significantly contributed to explaining the variance in learners' perception of L2 sounds. Attention control and acoustic short- term memory were related to learners' perception of cross-language phonetic distance. Contrary to our predictions, larger phonological short-term memory and acoustic short-term memory capacities were associated with lower degree of perceived phonetic distance between L2 and L1 sounds. In addition, lower attention control was related to faster and more accurate discrimination of L2 sounds. Taken together, our findings indicate that cognitive ability plays a role in L2 learners' acquisition of perceptual phonological competence. [cat] La mayoria de los aprendices de segundas lenguas (L2) tienen dificultades en la percepcion y la produccion del habla que resultan en un acento extranjero. Existe una gran variacion entre aprendices en la adquisicion fonologica de la L2. Se ha prestado relativamente poca atencion al papel de la capacidad cognitiva en la adquisicion de la competencia perceptiva en una L2. Esta tesis doctoral pretende llenar este vacio, abordando la siguiente pregunta: ? En que medida la capacidad cognitiva contribuye a la adquisicion de los sonidos de una L2? Nuestra hipotesis es que la memoria fonologica, la memoria acustica y el control de la atencion facilitan la adquisicion de la competencia perceptiva en una L2. Un grupo de 45 aprendices adultos catalan-espanol de ingles participaron en una bateria de pruebas de percepcion vocalica en la L2 y de pruebas cognitivas. Las vocales en el foco eran las comprendidas por los contrastes entre vocales inglesas /i/-/? /, /? /-/? /, /? /-/? /, /? /-/ae/ y /? /-/ae/. La capacidad de los aprendices de percibir una distancia fonetica entre estas vocales y las de su lengua materna (L1) y su exito en establecer vocales de la L2 se evaluaron por medio de una tarea de asimilacion perceptiva y una tarea de discriminacion de vocales, respectivamente. La contribucion de la memoria fonologica, la memoria acustica y el control de la atencion se examino relacionando las medidas cognitivas con la percepcion vocalica en la L2. Los resultados obtenidos en parte confirman la hipotesis. Las capacidades cognitivas contribuyeron significativamente a explicar la variacion en la percepcion vocalica en una L2. El control de la atencion y la memoria acustica contribuyeron significativamente a la percepcion de la distancia fonetica entre los sonidos de la L2 y la L1. La memoria fonologica y la memoria acustica se asociaron con un mayor grado de similitud percibida entre los sonidos de la L2 y la L1. Una menor capacidad del control de la atencion se relaciono con una percepcion mas precisa de oposiciones vocalicas de la L2. Los resultados sugieren que la capacidad cognitiva desempena un papel en la adquisicion de la competencia perceptiva en una L2.