Characterizing the distinctive acoustic cues of Mandarin tones

Changes to Mandarin vowel and lexical tone acoustics in clear speech production

This study examines the effects of clear speech on the acoustics of vowels and lexical tones in Mandarin. Thirty female speakers produced both casual and clear speech, with target words embedded in carrier sentences. Clear speech was associated with an expansion of vowel space area and a shift in vowel space distribution driven by higher F1 for /a/ and lower F2 for /u/. Tone space area increased in clear speech but showed no clear interaction with vowel type. Clear speech was associated with changes in pitch and timing parameters but not equally so across all tones. In general, clear speech tones exhibited greater mean, slope and range of fundamental frequency, longer durations, and reduced harmonic-to-noise ratio. A principal component analysis identified pitch change as the primary psychoacoustic parameter, while pitch height and duration were secondary. A logistic regression of principal components revealed an apparent coupling between duration and pitch change in casual speech that was not apparent in clear speech. Heightened contrasts of lexical tones in clear speech may therefore be associated with an increase in degrees of freedom for more precise control over individual tone parameters, independent of vowel characteristics.

"Panda" or "Bear, cat": Mandarin-speaking preschoolers use duration and pitch to distinguish compounds and lists

Compounds (e.g., jellybeans) and list forms (e.g., jelly, beans) can be distinguished by the presence or absence of boundaries, marked by durational and pitch cues. Studies have shown that 5-year-olds learning English have acquired both cues for distinguishing compounds and lists. However, it is not clear how and when this ability is acquired by children speaking tonal languages, such as Mandarin. This study examined whether Mandarin-speaking preschoolers can use durational and pitch cues to distinguish compounds and lists and whether their productions are adult-like. Thirty-one 4-year-olds, 34 5-year-olds, 29 6-year-olds, and 43 adults participated in an elicited production experiment. Results showed that similar to English-speaking preschoolers, Mandarin-speaking preschoolers can use durational cues to mark boundaries, triggering appropriate pitch changes for distinguishing compounds and lists, though these were not fully adult-like, even in the oldest age group.

Perception and Production of Pitch Information in Mandarin-Speaking Children with Autism Spectrum Disorders

This study investigated the categorical perception (CP) of linguistic pitch (lexical tones) and nonlinguistic pitch (pure tones), as well as tonal production in Mandarin-speaking children with autism spectrum disorders (ASD). A total of 26 Mandarin-speaking children with ASD and 29 age-matched typically developing (TD) children were recruited for this study. The Mandarin T2-T3 contrast and corresponding pure tones with identical pitch contours were adopted to assess the nuanced pitch processing abilities of the child participants via the CP paradigm. Accordingly, tonal production was focused on T2 and T3 with analyses of the dynamic pitch contours and tonal differentiation. Mandarin-speaking children with ASD exhibited atypical CP for linguistic pitch in comparison with their TD peers. However, the categorization of linguistic pitch exceeded that of nonlinguistic pitch among the ASD participants, indicating a global over local processing pattern contrary to autistic individuals in non-tonal languages. Additionally, despite atypical pitch contours in producing T2 and T3, the ASD group showed comparable differentiable degrees of the two tones in production to the TD group. Findings of this study served as a foray into contesting current theories' claims of local bias and/or global impairment in the autistic population, prompting further inspections on individuals with different language backgrounds and stimuli processing with various complexities. Additionally, findings of this study underscore the necessity of developing tailored assessments and interventions to enhance the perception and production of complex and confusable tones, thereby improving perceptual robustness and communication skills in Mandarin-speaking children with ASD.

High variability phonetic training facilitates perception-to-production transfer in Mandarin-speaking children with cochlear implants: An acoustic investigation

This study primarily aimed to evaluate the effectiveness of high variability phonetic training (HVPT) for children with cochlear implants (CIs) via the cross-modal transfer of perceptual learning to lexical tone production, a scope that has been largely neglected by previous training research. Sixteen CI participants received a five-session HVPT within a period of three weeks, whereas another 16 CI children were recruited without receiving any formal training. Lexical tone production was assessed with a picture naming task before the provision (pretest) and immediately after (posttest) and ten weeks after (follow-up test) the completion of the training protocol. The production samples were coded and analyzed acoustically. Despite considerable distinctions from the typical baselines of normal-hearing peers, the trained CI children exhibited significant improvements in Mandarin tone production from pretest to posttest in pitch height of T1, pitch slope of T2, and pitch curvature of T3. Moreover, the training-induced acoustic changes in the concave characteristic of the T3 contour was retained ten weeks after training termination. This study represents an initial acoustic investigation on HVPT-induced benefits in lexical tone production for the pediatric CI population, which provides valuable insights into applying this perceptual training technique as a viable tool in clinical practices.

Modelling Mandarin tone perception-production link through critical perceptual cues

Theoretical accounts posit a close link between speech perception and production, but empirical findings on this relationship are mixed. To explain this apparent contradiction, a proposed view is that a perception-production relationship should be established through the use of critical perceptual cues. This study examines this view by using Mandarin tones as a test case because the perceptual cues for Mandarin tones consist of perceptually critical pitch direction and noncritical pitch height cues. The defining features of critical and noncritical perceptual cues and the perception-production relationship of each cue for each tone were investigated. The perceptual stimuli in the perception experiment were created by varying one critical and one noncritical perceptual cue orthogonally. The cues for tones produced by the same group of native Mandarin participants were measured. This study found that the critical status of perceptual cues primarily influenced within-category and between-category perception for nearly all tones. Using cross-domain bidirectional statistical modelling, a perception-production link was found for the critical perceptual cue only. A stronger link was obtained when within-category and between-category perception data were included in the models as compared to using between-category perception data alone, suggesting a phonetically and phonologically driven perception-production relationship.

Phonetic and Phono-Lexical Accuracy of Non-Native Tone Production by English-L1 and Mandarin-L1 Speakers

Lexical tones are known to be a challenging aspect of speech to acquire in a second language, but several factors are known to affect tone learning facility, such as L1 tonal status (whether a learner's L1 is tonal or not), tone type (the shape of the tones to be acquired), and individual extralinguistic factors (such as musicianship, pitch aptitude, and working memory). Crucially, most of our knowledge of the effect of these factors is based on evidence from perception. The production side of tone learning and the origins of individual variability in learning facility remain relatively understudied. To this end, this study investigated non-native tone production-both in terms of phonetic accuracy in a pseudoword imitation task and in terms of phono-lexical accuracy in a picture-naming task-by English-L1 and Mandarin-L1 speakers. Results show that L1 tonal status and tone type dynamically affected both imitation and picture-naming accuracy, as there were specific accuracy patterns for the English and Mandarin groups. Production accuracy was further facilitated by individual musical experience, working memory, and pitch aptitude. This study's findings add to the currently limited literature on how both language-specific and individual extralinguistic factors modulate non-native tone processing in the speaking modality.

F0 range instead of F0 slope is the primary cue for the falling tone of Mandarin

It has been well known that rising/falling pitch is employed to distinguish the rising (R) or falling (F) tones from the high-level (H) tone in Mandarin, but whether F0 range or F0 slope is the more critical F0 cue to perception is still inconclusive. To clarify this issue quantitatively, we took the F tone as the test case, and conducted two-alternative forced choice identification tests on two types of two-dimensional high-level-falling (H-F) tonal continua, one of which was manipulated along F0 range and duration ("F0 range continuum") while the other along F0 slope and duration ("F0 slope continuum"). Experimental results indicated that F0 range was the primary cue because it resulted in a more robust (less duration-dependent) perceptual boundary than F0 slope. Meanwhile, the perceptual boundary in F0 range was not fully independent of but mildly modulated by duration, suggesting that duration (or equivalently, F0 slope) played a supplementary role in identifying the H-F tonal contrast.

Preoperative neoadjuvant chemotherapy in patients with breast cancer evaluated using strain ultrasonic elastography

BACKGROUND

The incidence of breast cancer in China is increasing while its mortality rate is decreasing. The annual breast cancer incidence in China is 39.2 million, accounting for two-thirds of the urban population. In China, breast cancer is the fifth most common malignant tumor overall and the most common in women, accounting for 17% of female malignant tumors.

AIM

To investigate the accuracy of strain ultrasound elastography (SUE) on the evaluation of preoperative neoadjuvant chemotherapy (NAC) in breast cancer.

METHODS

Overall, 90 patients with breast cancer treated at our hospital between January 2018 and February 2019 were selected for this study. The patients received six cycles of NAC with docetaxel, epirubicin, and cyclophosphamide. Surgical treatment was also performed, and pathological reactivity was assessed. The patients were evaluated using conventional ultrasonography and SUE before biopsy. The differences between groups were analyzed to calculate the mean and standard deviation with significance measured using a t-test, while multivariate analysis was performed using logistic regression analysis.

RESULTS

Of the patients analyzed, 20 had a pathological complete remission (pCR) while 70 did not achieve pCR after NAC. The ratio of the elastic strain ratio (SR) and elastic score of 4–5 in patients with pCR were 5.5 ± 1.16 and 15.00%, respectively; these were significantly lower than those in patients without pCR (85%) and significantly higher than in patients without pCR (14%). SR and elastic score 4–5 were independent factors influencing NAC efficacy (OR=0.644, 1.426 and 1.366, respectively, P < 0.05). SR was positively correlated with elasticity score (r_s = 0.411, P < 0.05). The area under the receiver operator characteristic curve of SR and SR combined with elastic score in predicting patients without pCR was 0.822 and 0.891, respectively (P < 0.05).

CONCLUSION

Strain ultrasonic elastography may be used to evaluate the effects of preoperative NAC in patients with breast cancer.

Principal component decomposition of acoustic and neural representations of time-varying pitch reveals adaptive efficient coding of speech covariation patterns

Understanding the effects of statistical regularities on speech processing is a central issue in auditory neuroscience. To investigate the effects of distributional covariance on the neural processing of speech features, we introduce and validate a novel approach: decomposition of time-varying signals into patterns of covariation extracted with Principal Component Analysis. We used this decomposition to assay the sensory representation of pitch covariation patterns in native Chinese listeners and non-native learners of Mandarin Chinese tones. Sensory representations were examined using the frequency-following response, a far-field potential that reflects phase-locked activity from neural ensembles along the auditory pathway. We found a more efficient representation of the covariation patterns that accounted for more redundancy in the form of distributional covariance. Notably, long-term language and short-term training experiences enhanced the sensory representation of these covariation patterns.

Acoustic analysis of tone production in Mandarin-speaking bimodal cochlear implant users

The benefit of using a hearing aid with a cochlear implant (bimodal hearing) has been demonstrated for tone perception under certain conditions. The present study evaluated bimodal effects for tone production by comparing performance between a bimodal and a unimodal implant group. Results showed that acoustic differentiation of tones produced by the bimodal group was better than the unimodal implant group, and performance was dependent on the subject's acoustic thresholds but not related to implant experience or age at implantation. The findings support the use of amplified acoustic hearing in conjunction with the implant for better development of pitch production.

Computational Modelling of Tone Perception Based on Direct Processing of f0 Contours

It has been widely assumed that in speech perception it is imperative to first detect a set of distinctive properties or features and then use them to recognize phonetic units like consonants, vowels, and tones. Those features can be auditory cues or articulatory gestures, or a combination of both. There have been no clear demonstrations of how exactly such a two-phase process would work in the perception of continuous speech, however. Here we used computational modelling to explore whether it is possible to recognize phonetic categories from syllable-sized continuous acoustic signals of connected speech without intermediate featural representations. We used Support Vector Machine (SVM) and Self-organizing Map (SOM) to simulate tone perception in Mandarin, by either directly processing f0 trajectories, or extracting various tonal features. The results show that direct tone recognition not only yields better performance than any of the feature extraction schemes, but also requires less computational power. These results suggest that prior extraction of features is unlikely the operational mechanism of speech perception.

The contrast between clear and plain speaking style for Mandarin tones

We examine the acoustic characteristics of clear and plain conversational productions of Mandarin tones. Twenty-one native Mandarin speakers were asked to produce a selection of Mandarin words in both plain and clear speaking styles. Several tokens were gathered for each of the four tones giving a total of 2045 productions. Six critical tonal cues were computed for each production: fundamental frequency (F0) mean, slope, and second derivative, duration, mean intensity, and a binary variable coding whether the production involved creaky voice. A linear mixed-effects regression model was used to explore how these cues changed with respect to the clear versus plain distinction for each tone, with speaking style as the fixed effect and speaker being a random effect. The strongest effects detected were that duration and mean intensity increased in clear speech across speakers and tones. Tones 2 and 3 increased in mean F0 and Tone 4 increased its slope. An additional finding was that, for contour tones, speakers accomplished the increase in duration by stretching out the tone contours in time while largely not changing the F0 range. These results are discussed in terms of signal-based (affecting all tones) and code-based (enhancing contrast between tones) change.

Effects of Cognitive Load on the Categorical Perception of Mandarin Tones

Purpose This study investigated the effect of cognitive load (CL) on the categorical perception (CP) of Mandarin lexical tones to discuss the application of the generalized pulse-skipping hypothesis. This hypothesis assumes that listeners might miss/skip temporal pulses and lose essential speech information due to CL, which consequently affects both the temporal and spectral dimensions of speech perception. Should CL decrease listeners' pitch sensitivity and impair the distinction of tone categories, this study would support the generalized pulse-skipping hypothesis. Method Twenty-four native Mandarin-speaking listeners were recruited to complete a dual-task experiment where they were required to identify or discriminate tone stimuli while concurrently memorizing six Chinese characters or graphic symbols. A no-load condition without a memory recall task was also included as a baseline condition. The position of categorical boundary, identification slope, between- and within-category discrimination, and discrimination peakedness were compared across the three conditions to measure the impact of CL on tone perception. The recall accuracy of Chinese characters and graphic symbols was used to assess the difficulty of memory recall. Results Compared with the no-load condition, both load conditions showed a boundary shift to Tone 3, shallower identification slope, poorer between-category discrimination, and lower discrimination peakedness. Within-category discrimination was negatively affected by CL in the graphic symbol condition only, not in the Chinese character condition. Conclusions CL degraded listeners' sensitivity to subtle fundamental frequency changes and impaired CP of Mandarin lexical tones. This provides support for the generalized pulse-skipping hypothesis. Besides, the involvement of lexical information modulated the effect of CL.

High-Variability Phonetic Training Benefits Lexical Tone Perception: An Investigation on Mandarin-Speaking Pediatric Cochlear Implant Users

Purpose Lexical tone perception is known to be persistently difficult for individuals with cochlear implants (CIs). The purpose of this study was to evaluate the efficacy of high-variability phonetic training (HVPT) in improving Mandarin tone perception for native-speaking children with CIs. Method A total of 28 Mandarin-speaking pediatric CI recipients participated in the study. Half of the children with CIs received a five-session HVPT within a period of 3 weeks. Identification and discrimination of lexical tones produced by familiar talkers (used during training) and novel talkers (not used during training) were measured before, immediately after, and 10 weeks after training termination. The other half untrained children served as control for the identical pre- and posttests. Results Lexical tone perception significantly improved in both trained identification task and untrained discrimination task for the trainees. There was also a significant effect in transfer of learning to perceiving tones produced by novel talkers. Moreover, training-induced gains were retained for up to 10 weeks after training. By comparison, no significant pre-post changes were observed in the control group. Conclusion The results provide the first systematical assessment for the efficacy of the HVPT protocol for Mandarin-speaking pediatric CI users with congenital hearing loss, which supports the clinical utility of intensive short-term HVPT in these children's rehabilitative regimens.

Acoustic Assessment of Tone Production of Prelingually-Deafened Mandarin-Speaking Children With Cochlear Implants

Objective

The purpose of the present study was to investigate Mandarin tone production performance of prelingually deafened children with cochlear implants (CIs) using modified acoustic analyses and to evaluate the relationship between demographic factors of those CI children and their tone production ability.

Methods

Two hundred seventy-eight prelingually deafened children with CIs and 173 age-matched normal-hearing (NH) children participated in the study. Thirty-six monosyllabic Mandarin Chinese words were recorded from each subject. The fundamental frequencies (F0) were extracted from the tone tokens. Two acoustic measures (i.e., differentiability and hit rate) were computed based on the F0 onset and offset values (i.e., the tone ellipses of the two-dimensional [2D] method) or the F0 onset, midpoint, and offset values (i.e., the tone ellipsoids of the 3D method). The correlations between the acoustic measures as well as between the methods were performed. The relationship between demographic factors and acoustic measures were also explored.

Results

The children with CIs showed significantly poorer performance in tone differentiability and hit rate than the NH children. For both CI and NH groups, performance on the two acoustic measures was highly correlated with each other (r values: 0.895–0.961). The performance between the two methods (i.e., 2D and 3D methods) was also highly correlated (r values: 0.774–0.914). Age at implantation and duration of CI use showed a weak correlation with the scores of acoustic measures under both methods. These two factors jointly accounted for 15.4–18.9% of the total variance of tone production performance.

Conclusion

There were significant deficits in tone production ability in most prelingually deafened children with CIs, even after prolonged use of the devices. The strong correlation between the two methods suggested that the simpler, 2D method seemed to be efficient in acoustic assessment for lexical tones in hearing-impaired children. Age at implantation and especially the duration of CI use were significant, although weak, predictors for tone development in pediatric CI users. Although a large part of tone production ability could not be attributed to these two factors, the results still encourage early implantation and continual CI use for better lexical tone development in Mandarin-speaking pediatric CI users.