Modeling Lexical Tones for Speaker Discrimination.

Fundamental frequency (F0) has been widely studied and used in the context of speaker discrimination and forensic voice comparison casework, but most previous studies focused on long-term F0 statistics. Lexical tone, the linguistically structured and dynamic aspects of F0, has received much less research attention. A main methodological issue lies on how tonal F0 should be parameterized for the best speaker discrimination performance. This paper compares the speaker discriminatory performance of three approaches with lexical tone modeling: discrete cosine transform (DCT), polynomial curve fitting, and quantitative target approximation (qTA). Results show that using parameters based on DCT and polynomials led to similarly promising performance, whereas those based on qTA generally yielded relatively poor performance. Implications modeling surface tonal F0 and the underlying articulatory processes for speaker discrimination are discussed.

English Prosodic Focus Marking by Cantonese Trilingual Children With and Without Autism Spectrum Disorder.

PURPOSE: The current study investigated English prosodic focus marking by autistic and typically developing (TD) Cantonese trilingual children, and examined the potential differences in this regard compared to native English-speaking children. METHOD: Forty-eight participants were recruited with 16 speakers for each of the three groups (Cantonese-speaking autistic [CASD], Cantonese-speaking TD [CTD], and English-speaking TD [ETD] children), and prompt questions were designed to elicit desired focus type (i.e., broad, narrow, and contrastive focus). Mean duration, mean fundamental frequency (F0), F0 range, mean intensity, and F0 curves were used as the acoustic correlates for linear mixed-effects model fitting and functional data analyses in relation to groups and focus conditions (i.e., broad, narrow, and contrastive pre-, on-, and post-focus). RESULTS: The CTD group had post-focus compression (PFC) patterns via reducing mean duration, narrowing F0 range, and lowering mean F0, F0 curve, and mean intensity for words under both narrow and contrastive post-focus conditions, while the CASD group only had shortened mean duration and lowered F0 curves. However, neither the CTD group nor CASD group showed much of on-focus expansion (OFE) patterns. The ETD group marked OFE by increasing mean duration, mean F0, mean intensity, and higher F0 curve for words under on-focus conditions. CONCLUSIONS: The CTD group utilized more acoustic cues than the CASD group when it comes to PFC. The ETD group differed from the CASD and CTD groups in the use of OFE. Furthermore, both the CASD and CTD groups showed positive first language transfer in the use of duration and intensity and, potentially, successful acquisition in the use of F0 for prosodic focus marking. Meanwhile, the differences in the use of OFE between the Cantonese-speaking and English-speaking groups, not PFC, might indicate that Cantonese-speaking children acquire PFC prior to OFE.