July 26, 2012 - 3 Posters Accepted to 164th Meeting of the Acoustical Society of America

We are happy to announce that three of the LABlab's projects have had posters accepted to the Acoustical Society of America's upcoming conference, taking place in Kansas City, Missouri, October 22-26, 2012.

Effects of acoustic and linguistic aspects on Japanese pitch accent processing - Xianghua Wu, Saya Kawase, and Yue Wang

The influence of visual information on the perception of Japanese-accented speech - Saya Kawase, Beverly Hannah, and Yue Wang

Cross-language assimilation of lexical tone - Alexander, J.A. and Wang, Y.

Abstracts

Effects of acoustic and linguistic aspects on Japanese pitch accent processing
Xianghua Wu, Saya Kawase, and Yue Wang

This study investigates the hemispheric processing of Japanese pitch accent by native and non-native listeners. The non-natives differ in their first (L1) and second (L2) language experience with prosodic pitch, including Mandarin (tonal L1) and English (non-tonal L1) listeners with or without Japanese learning experience.  All listeners completed a dichotic listening test in which minimal pairs differing in pitch accent were presented. Overall, the results demonstrate a right hemisphere lateralization across groups, indicating holistic processing of temporal cues as the pitch accent patterns span across disyllabic domain. Moreover, the three pitch accent patterns reveal different degrees of hemispheric dominance, presumably attributable to the acoustic cues to each pattern which involve different hemispheric asymmetries. The results also reveal group difference, reflecting the effects of linguistic experience. Specifically, the English listeners with no Japanese background, compared to the other groups, exhibit greater variance in hemispheric dominance as a function of pitch accent difference, showing a greater reliance on acoustic cues when linguistic information is lacking. Together, the findings suggest an interplay of acoustic and linguistic aspects in the processing of Japanese pitch accent but showing a more prominent acoustic influence. [Research supported by NSERC]

The influence of visual information on the perception of Japanese-accented speech
Saya Kawase, Beverly Hannah, and Yue Wang

This study examines how visual information in nonnative speech affects native listener judgments of second language (L2) speech production. Native Canadian English listeners perceived three English phonemic contrasts (/b-v, θ-s, l-ɹ/) produced by native Japanese speakers as well as native Canadian English speakers as controls. Among the stimuli, / v, θ, l, ɹ/ are not existent in the Japanese consonant inventory. These stimuli were presented under audio-visual (AV), audio-only (AO), and visual-only (VO) conditions. The results showed that while overall perceptual judgments of the nonnative phonemes (/v, θ, l, ɹ/) were significantly less accurate / less intelligible than the native phonemes (/b,s/), the English listeners perceived the Japanese productions of the phonemes /v, θ, b,s/ as significantly more intelligible when presented in AV compared to the AO condition. However, the Japanese production of /ɹ/ was perceived as less intelligible in the AV compared to the AO condition.  Further analysis revealed that a significant number of Japanese productions of /ɹ/ lacked lip-rounding, indicating that nonnative speakers’ incorrect articulatory configurations may decrease intelligibility. These results suggest that visual cues in L2 speech productions may be either facilitative or inhibitory in native perception of L2 accented-speech. [Research supported by SFU and SSHRC]

Cross-language assimilation of lexical tone
Alexander, J.A. and Wang, Y.

We extend to lexical-tone systems a model of second-language perception, the Perceptual Assimilation Model (PAM) [Best & Tyler, 2007], to examine whether/how native-language lexical-tone inventory composition influences perception of novel tone. Native listeners of Cantonese, Thai, and Mandarin perform a tone mapping-rating assimilation task. Listeners hear CV syllables bearing all tones of Cantonese, Thai, Mandarin, and Yoruba – languages with different tone inventories. They (1) map the tone they hear to the nearest native tone category, and (2) provide a goodness rating on a 5-point scale (5 = perfect). As predicted by the PAM, listeners assimilated non-native tones to the phonetically-closest native tone categories. Listeners attended primarily to pitch-contour, and secondarily to pitch-height, contrasts for the mappings. E.g., Mandarin listeners assimilated the Thai high “level” (phonetically mid-to-high-rising) tone to Mandarin rising tone 76% of the time, and to Mandarin high-level tone only 22% of the time. Also as predicted, all novel tones did not assimilate equally well to native categories; mappings received ratings between 2.9-4.1, averaging 3.5. The groups’ different patterns of results indicate that novel-tone perception is influenced by experience with the native-language tone inventory, and that listeners attend to gradient phonetic detail to assimilate novel tones to native-tone categories. This work is supported by NSF grant 0965227 to J.A.

Abstract

In an investigation of how lexical tone is perceived and processed at the phonetic and phonological levels, listeners from diverse language backgrounds participated in three perceptual studies. In the first, native Mandarin and Thai listeners assimilated non-native tones to their native tone categories. Results indicated that occurrence of a lower-level phonetic and a higher-level phonological assimilation process was related to listeners' tone experience, as inexperienced listeners recognized only the phonetic distinctions, whereas experienced listeners were sensitive to both phonetic and phonological distinctions between native and non-native tone categories.

In the second study, native Mandarin, Thai and English listeners participated in a forced-choice tone perception test in which they identified the four Mandarin tone categories. Identification accuracy and confusion patterns revealed that previous tone experience predicted tone perception at the phonetic and phonological levels. Better performance was demonstrated for native than non-native, and experienced than inexperienced listeners. Experienced Thai listeners also showed more native-like performance than experienced English listeners. Lexical information from the carrier words was also found to help Mandarin and English listeners recognize difficult tones.

In the third study, participants from the second one completed a dichotic listening test assessing tone lateralization in the brain. The results demonstrated a strong influence of acoustic properties, as tones with dynamic F0 contours were lateralized to the left hemisphere while those with flatter F0 contours were lateralized to the right hemisphere. Meanwhile, native and non-native tone experience was associated with a larger degree of left hemisphere activation for Mandarin and experienced Thai listeners relative to those in the remaining groups.

In summary, these three studies indicate tone perception and processing at both phonetic and phonological levels. In relation to tone experience, inexperienced listeners may attach more importance to phonetic variation while experienced listeners are sensitive to both phonetic and phonological differences. In terms of theoretical contributions, tone perception results extend the current models of speech perception to the suprasegmental level while tone lateralization results provide evidence supporting the acoustic and functional hypotheses.

Members of Examining Committee:
Chair, Dr. Chung-hye Han
Sr. Supervisor, Dr. Murray Munro
Co-Supervisor, Dr. Yue Wang
Internal Examiner, Dr. Christian Guilbault
External Examiner, Dr. Valter Ciocco