Individual strategies in second language perception and production; auditorily driven VOT lengthening

This paper is part of larger research focused on the processes involved in the acquisition of new phonetic control regimes in L2 learning. In prior experiments, we have been studying the auditory perceptual factors likely to exert influences on speech sounds production by the subjects in a simple repetition task (i.e., in the absence of any instruction related to the idea of learning a new language or changing in any way one's usual way of speaking). Our findings showed that varying the model provokes changes of the production in the direction of the model. Nevertheless, our first analyses were mainly about groups and overall tendencies. Here, on the contrary, we focus on individuals as such and try to understand their perceptual and productive strategies. The data have been collected in experiments aiming at changing the time course of phonetic events during the production of initial oral stop consonants: ten natives French were exposed to stimuli with phonetic structures close to the ones of English realizations (lengthened VOT, aspiration). Stimuli were derived from natural productions by a native American English speaker, thanks to artificial alterations along two dimensions (VOT and burst intensity). In a repetition task (simply repeat 'as faithfully as possible'), the subjects were asked to simply repeat the acoustically controlled stimuli (realizations of /ta/). Their perceptual behavior was studied in a prior (AB discrimination) and in a posterior (judgments of similarity) task. The productions were acoustically analyzed and moreover randomly presented to a board of American English listeners, who had to assess them in terms of typicality. The results show that most the subjects are successful in producing a lengthened VOT; however, they exhibit highly variable perceptual sensitivities to the controlled acoustic cues, and variable VOT lengthening, together with variable side effects (e.g., vowel lengthening).