Training Japanese listeners to identify English /r/ and /l/. II: The role of phonetic environment and talker variability in learning new perceptual categories

Abstract

Two experiments were carried out to extend Logan et al.'s recent study [J. S. Logan, S. E. Lively, and D. B. Pisoni, J. Acoust. Soc. Am. 89, 874-886 (1991)] on training Japanese listeners to identify English /r/ and /l/. Subjects in experiment 1 were trained in an identification task with multiple talkers who produced English words containing the /r/-/l/ contrast in initial singleton, initial consonant clusters, and intervocalic positions. Moderate, but significant, increases in accuracy and decreases in response latency were observed between pretest and posttest and during training sessions. Subjects also generalized to new words produced by a familiar talker and novel words produced by an unfamiliar talker. In experiment 2, a new group of subjects was trained with tokens from a single talker who produced words containing the /r/-/l/ contrast in five phonetic environments. Although subjects improved during training and showed increases in pretest-posttest performance, they failed to generalize to tokens produced by a new talker. The results of the present experiments suggest that variability plays an important role in perceptual learning and robust category formation. During training, listeners develop talker-specific, context-dependent representations for new phonetic categories by selectively shifting attention toward the contrastive dimensions of the non-native phonetic categories. Phonotactic constraints in the native language, similarity of the new contrast to distinctions in the native language, and the distinctiveness of contrastive cues all appear to mediate category acquisition.

Supervised and unsupervised learning of multidimensionally varying non-native speech categories

“…The supervised learning procedure in Experiment 1 thus was comparable to the typical procedure used in visual category learning studies and in speechcontrast training studies (e.g., Bradlow, Akahane-Yamada, Pisoni, & Tohkura, 1997;Greenspan, Nusbaum, & Pisoni, 1988;Lively, Logan, & Pisoni, 1993). The unsupervised learning procedure in Experiment 2 was more comparable to the situation of infants learning their first language.…”

Audiovisual Training Effects on L2 Speech Perception and Production

“…The stimuli and training process were designed according to the principles of High Variability Phonetic Training (HVPT thereafter)-"natural" and "variability" (Lively et al, 1993;Logan et al, 1993;Bradlow et al, 1997). HVPT is predicted to be able to direct language learners' attention towards relevant phonetic cues by providing them with stimuli of high-variability in different phonetic contexts.…”

Individual differences in the acquisition of second language phonology

“…Also, given that these sounds are synthetic, they were unfamiliar to the participants and thus optimal for use in a learning study. On the other hand, it is known that training with naturalistic stimuli (or with stimuli generated by more sophisticated synthesizers than the one we used) which contain within-category acoustic variability is more generalisable to new stimuli (Lively, Logan, & Pisoni, 1993). Therefore, although we validate the synthetic stimuli with native speakers of Indian languages in a pilot study (see below), the generalisability-related implications of our study are limited.…”