Second language learners of English often experience difficulties in English lexical stress perception. This has traditionally been attributed to transfer of prosodic unit or settings from their first language (L1). Similarly, the problem of Chinese learners with English stress perception was assumed to arise from tonal transfer. However, little research has been devoted to the investigation of the phonetic details of second language (L2) stress perception. The present research focuses on the perception of English lexical stress by Chinese learners of English. The purpose of this study is to reveal the use of acoustic cues in stress perception by Chinese learners of English. In the experiment, F0, duration and intensity were manipulated, each with five steps, on three disyllabic nonsense words to result in a total of 375 nonsense tokens. A group of native speakers of English (NE) and a group of Chinese learners of English (CE) participated in the study and judged whether the stress was on the first or second syllable in the test stimuli. The responses of Chinese learners of English in stress judgment were compared against the baseline of native English speakers. The statistical tests of reliance measures and logistic regression models were used in data analysis. Results indicated that, similar to NE participants, performance by CE participants showed systematic variation as a result of the manipulation of the three acoustic cues. However, CEs were different from NEs in their reliance on the three cues. CE had significantly lower duration and intensity reliance scores but significantly higher F0 than NE. In logistic regression analysis, compared to the NE group, F0 contributed most to the CE models, while the contribution of duration and intensity was minimal. It is concluded from this study that while all three cues have significant effects on stress perception for native English speakers, only F0 has a decisive effect on stress judgments by Chinese learners of English. This study reveals that, rather than transfer of tone at the phonological level, there is transfer of reliance on F0 in the acquisition of L2 English stress. It is suggested that the investigation of phonetic details of learners’ problems with L2 stress acquisition is necessary for L2 speech learning theories and also for L2 stress teaching.

Bien qu’il existe un large consensus de la communauté scientifique quant au rôle des indices acoustiques dans la compréhension de la parole, les mécanismes exacts permettant la transformation d’un flux acoustique continu en unités linguistiques élémentaires demeurent aujourd’hui largement méconnus. Ceci est en partie dû à l’absence d’une méthodologie efficace pour l’identification et la caractérisation des primitives auditives de la parole. Depuis les premières études de l’interface acoustico-phonétique par les Haskins Laboratories dans les années 50, différentes approches ont été proposées ; cependant, toutes sont fondamentalement limitées par l’artificialité des stimuli utilisés, les contraintes du protocole expérimental et le poids des connaissances a priori nécessaires. Le présent travail de thèse s’est intéressé { la mise en oeuvre d’une nouvelle méthode tirant parti de la situation de compréhension de parole dégradée pour mettre en évidence les indices acoustiques utilisés par l’auditeur.Dans un premier temps, nous nous sommes appuyés sur la littérature dans le domaine visuel en adaptant la méthode des Images de Classification à une tâche auditive de catégorisation de phonèmes dans le bruit. En reliant la réponse de l’auditeur { chaque essai à la configuration précise du bruit lors de cet essai, au moyen d’un Modèle Linéaire Généralisé, il est possible d’estimer le poids des différentes régions temps-fréquence dans la décision. Nous avons illustré l’efficacité de notre méthode, appelée Image de Classification Auditive, à travers deux exemples : une catégorisation /aba/-/ada/, et une catégorisation /da/-/ga/ en contexte /al/ ou /aʁ/. Notre analyse a confirmé l’implication des attaques des formants F2 et F3, déjà suggérée par de précédentes études, mais a également permis de révéler des indices inattendus. Dans un second temps, nous avons employé cette technique pour comparer les résultats de participants musiciens experts (N=19) ou dyslexiques (N=18) avec ceux de participants contrôles. Ceci nous a permis d’étudier les spécificités des stratégies d’écoute de ces différents groupes.L’ensemble des résultats suggèrent que les Images de Classification Auditives pourraient constituer une nouvelle approche, plus précise et plus naturelle, pour explorer et décrire les mécanismes { l’oeuvre au niveau de l’interface acoustico-phonétique. / There is today a broad consensus in the scientific community regarding the involvement of acoustic cues in speech perception. Up to now, however, the precise mechanisms underlying the transformation from continuous acoustic stream into discrete linguistic units remain largely undetermined. This is partly due to the lack of an effective method for identifying and characterizing the auditory primitives of speech. Since the earliest studies on the acoustic–phonetic interface by the Haskins Laboratories in the 50’s, a number of approaches have been proposed; they are nevertheless inherently limited by the non-naturalness of the stimuli used, the constraints of the experimental apparatus, and the a priori knowledge needed. The present thesis aimed at introducing a new method capitalizing on the speech-in-noise situation for revealing the acoustic cues used by the listeners.As a first step, we adapted the Classification Image technique, developed in the visual domain, to a phoneme categorization task in noise. The technique relies on a Generalized Linear Model to link each participant’s response to the specific configuration of noise, on a trial-by-trail basis, thereby estimating the perceptual weighting of the different time-frequency regions for the decision. We illustrated the effectiveness of our Auditory Classification Image method through 2 examples: a /aba/-/ada/ categorization and a /da/-/ga/ categorization in context /al/ or /aʁ/. Our analysis confirmed that the F2 and F3 onsets were crucial for the tasks, as suggested in previous studies, but also revealed unexpected cues. In a second step, we relied on this new method to compare the results of musical experts (N=19) or dyslexics participants (N=18) to those of controls. This enabled us to explore the specificities of each group’s listening strategies.All the results taken together show that the Auditory Classification Image method may be a more precise and more straightforward approach to investigate the mechanisms at work at the acoustic-phonetic interface.