Behavioral and neurophysiological investigations of individual variation in cue weighting strategies (National Science Foundation #1827409 in collaboration with Ming Xiang and Jinghua Ou)

The perception of speech sounds often requires listeners to pay attention to multiple cues at once. The weighting of the relative importance of cues can nonetheless vary across individuals. Little is known regarding the sources of such variation, however. This project will investigate potential mechanisms underpinning such variability. The project will broaden the empirical database on which theories of speech perception and production are grounded as well as providing insights into first/second language acquisition and pedagogy in terms of the development of personalized training for individual language learners. The project will also introduce young women and under-represented minorities to STEM fields via the study of the language sciences through planned outreach programs. The findings from this project may inform clinical research on developmental or acquired perceptual and language impairments, and may also serve to inform research on speech related technologies.

This project focuses on two potential explanations for individual variability in cue weighting. Listeners might differ in early auditory encoding, which affects the reliability, hence weighting, of certain cues that support phonological contrasts. Listeners might also differ in cue integration strategy such that some utilize a continuous cue integration strategy whereby cue information is integrated as they become available, while others might employ a buffer strategy so that phonemic identification is postponed until all necessary information becomes available. This project will investigate individual variability in cue weighting using brainstem and cortical responses to speech sounds within the same individual, thus providing a comprehensive neurophysiological profile that underlies individual patterns of real-time cue weighting process, as measured with eye-movements

Comparative Cantonese Acquisition: Ethnic Minorities, Recent Immigrants, and Local Chinese Families in Hong Kong (in collaboration with Carol To at Hong Kong University and Yao Yao at Polytechnic University of Hong Kong)

Hong Kong has seen a continuous increase in the number of local children born to ethnic minority families with South Asian heritage and Chinese families that migrated from the mainland. These children speak a minority language as their mother tongue and belong to a minority culture within a larger community.

This project aims to examine the relationship between the language input received by these young children and the language the children are producing based on data in the Multi-ethnic Hong Kong Cantonese Corpus (MeHKCC). Specifically, we seek to study the quantity and quality of the Cantonese used by the children towards their caregivers and the Cantonese input from those caregivers. Our specific aims are (1) to establish a comparative corpus of Cantonese child speech as well as child directed speech (CDS) between toddlers and mothers who speak a South Asian language, Putonghua or local Cantonese as first language (L1); (2) to demonstrate the quantitative and qualitative differences of Cantonese produced by these three groups of children and mothers as they interact with each other; (3) to identify the contribution of variant pronunciations in Cantonese among the three groups in the recent sound changes in Hong Kong Cantonese (HKC).

The Linguistic Characteristics of Autism in Hong Kong: A Corpus Approach (in collaboration with Carol To at Hong Kong University)

There is a fundamental gap in understanding the nature of speech production in individuals with autism spectrum disorder (ASD), even though atypical language use is a core symptom in the clinical presentation and evaluation of ASD. The situation is even more acute for the speech production of ASD individuals whose native language is Cantonese as most research on ASD has been focused on English and other Western languages. Even within the Chinese context, ASD research has focused mainly on speakers of Mandarin, rather than other varieties of Chinese. The long-term goal of the proposed research is to further understanding of the precise phonetic characteristics of what constitutes patterns of atypical speech in Cantonese-speaking ASD individuals. The proposed research is significantbecause it will improve understanding and recognition of the clinical presentation of ASD in Hong Kong and the Greater Bay Area. Ultimately, such knowledge has the potential to inform the design of diagnostic and assessment tools to better capture the presence and severity of ASD symptoms among native Cantonese speakers in Hong Kong and the Greater Bay Area. In addition, the methods proposed will enable analysis of more representative and ecologically valid natural language samples, and may create opportunities for discovery of currently unknown speech features in individuals with ASD.