Development of perceptual similarity and discriminability: the perception of Russian phonemes by Chinese learners.

This study explored the perceptual assimilation and discrimination of Russian phonemes by three groups of Chinese listeners with differing Russian learning experience. A perceptual assimilation task (PAT) and a perceptual discrimination test (PDT) were conducted to investigate if/how L1-L2 perceptual similarity would vary as a function of increased learning experience, and the development of assimilation-discrimination relations. The PAT was analyzed via assimilation rates, dispersion K' values, goodness ratings and assimilation patterns. Results revealed an intriguing phenomenon that the perceived Mandarin-Russian similarity first increased from naïve listeners to intermediate learners and then decreased slightly in relatively advanced learners. This suggests that L1-L2 perceptual similarity is subject to learning experience and could follow a potential "rise and fall" developmental pattern. The PDT results were mostly in line with the assimilation-discrimination correspondence with more experience bringing out better discriminability in general. Yet the overall sensitivity d' values from the Chinese groups were relatively low, implying acoustic/articulatory effects on L2 discriminability aside from perceptual assimilation. The results were discussed under the frameworks of L2 Perceptual Assimilation Model, Speech Learning Model and L2 Linguistic Perception Model.

Production of Mandarin consonant aspiration and monophthongs in children with Autism Spectrum Disorder.

Impaired speech sound production adds difficulties to social communication in children with Autism Spectrum Disorder (ASD), while a limited attempt has been made to figure out the speech sound production among Mandarin-speaking children with ASD. The current study conducted both auditory-perceptual scoring and quantitative acoustic analysis of speech sound imitated by 27 Mandarin-speaking children with ASD (3.33-7.00 years) and 30 chronological-age-matched typically developing (TD) children. Auditory-perceptual scoring showed significantly lower scores for aspirated/unaspirated consonants and monophthongs in children with ASD. Moreover, the correlation between the developmental age of language and production accuracy in children with ASD emphasised the importance of language assessment. The quantitative acoustic analysis further indicated that the ASD group produced a much shorter voice onset time for aspirated consonants and showed a reduced vowel space than the TD group. Early interventions focusing on these production patterns should be introduced to improve the speech sound production in Mandarin-speaking children with ASD.

The Phonological Development of Mandarin Voiceless Affricates in Three- to Five-Year-Old Children.

This study investigates the phonological development of Mandarin voiceless affricates produced by Mandarin-speaking children. Thirty-six monolingual Mandarin-speaking children and twelve adults participated in a speech production task. Auditory-based transcription analysis and acoustic analysis were utilized to quantify the relative order of affricate acquisition. Both methods yielded earlier acquisition of alveopalatal affricates at age three than retroflex and alveolar affricates, whereas they differed in the acquisition order of retroflex and alveolar affricates. The former revealed that both retroflex and alveolar affricates were acquired at age five, regardless of aspiration, while the latter yielded earlier acquisition of retroflex than alveolar affricates. Possible reasons for the discrepancy are discussed in relation to the different nature of the two methods. Overall, the observed acquisition order of Mandarin voiceless affricates suggests that child speech development is a complex process, and is influenced by various factors including oromotor maturation and language-specific phoneme frequencies in the ambient language.

The Development of Categorical Perception of Segments and Suprasegments in Mandarin-Speaking Preschoolers.

This study investigated the developmental trajectories of categorical perception (CP) of segments (i.e., stops) and suprasegments (i.e., lexical tones) in an attempt to examine the perceptual development of phonological categories and whether CP of suprasegments develops in parallel with that of segments. Forty-seven Mandarin-speaking monolingual preschoolers aged four to six years old, and fourteen adults completed both identification and discrimination tasks of the Tone 1-2 continuum and the /pa/-/pha/ continuum. Results revealed that children could perceive both lexical tones and aspiration of stops in a categorical manner by age four. The boundary position did not depend on age, with children having similar positions to adults regardless of speech continuum types. The boundary width, on the other hand, reached the adult-like level at age six for lexical tones, but not for stops. In addition, the within-category discrimination score did not differ significantly between children and adults for both continua. The between-category discrimination score improved with age and achieved the adult-like level at age five for lexical tones, but still not for stops even at age six. It suggests that the fine-grained perception of phonological categories is a protracted process, and the improvement and varying timeline of the development of segments and suprasegments are discussed in relation to statistical learning of the regularities of speech sounds in ambient language, ongoing maturation of perceptual systems, the memory mechanism underlying perceptual learning, and the intrinsic nature of speech elements.

Applications of water-stable metal-organic frameworks in the removal of water pollutants: A review.

Because the pollutants produced by human activities have destroyed the ecological balance of natural water environment, and caused severe impact on human life safety and environmental security. Hence the task of water environment restoration is imminent. Metal-organic frameworks (MOFs), structured from organic ligands and inorganic metal ions, are notable for their outstanding crystallinity, diverse structures, large surface areas, adsorption performance, and excellent component tunability. The water stability of MOFs is a key requisite for their possible actual applications in separation, catalysis, adsorption, and other water environment remediation areas because it is necessary to safeguard the integrity of the material structure during utilization. In this article, we comprehensively review state-of-the-art research progress on the promising potential of MOFs as excellent nanomaterials to remove contaminants from the water environment. Firstly, the fundamental characteristics and preparation methods of several typical water-stable MOFs include UiO, MIL, and ZIF are introduced. Then, the removal property and mechanism of heavy metal ions, radionuclide contaminants, drugs, and organic dyes by different MOFs were compared. Finally, the application prospect of MOFs in pollutant remediation prospected. In this review, the synthesis methods and application in water pollutant removal are explored, which provide ways toward the effective use of water-stable MOFs in materials design and environmental remediation.

Effects of age and sex on voice onset time: Evidence from Mandarin voiceless stops.

Considerable studies have addressed effects of age and sex on voice onset time (VOT) in English. However, few studies have examined these effects on Mandarin stops. This study attempts to examine effects of age and sex on VOT in Mandarin. A total of 85 Mandarin-speaking children, aged 4-18 years old, and 13 adults as reference participated in a production experiment. Productions were elicited by reading target words in carrier phrases. Results showed that children aged 6-7 years old had longer VOTs than older ones for highly aspirated stops, and the same tendency was not observed for unaspirated stops. However, no linear developmental trend was observed for both highly aspirated and unaspirated stops. In addition, females displayed longer VOTs for highly aspirated stops and shorter for unaspirated stops, whereas significant sex differences in VOTs existed from 14 years old to adulthood for highly aspirated stops, and no significant sex differences in VOTs were found for unaspirated stops in each group, indicating that sex differences in VOTs varied with age and aspiration. The findings suggest that physiological changes in and differences between males and females provide account for some, but not all differences in VOTs across age and sex.