Tone perception ability of Cantonese-speaking children

Pitch Variation Skills in Cantonese Speakers With Apraxia of Speech After Stroke: Preliminary Findings of Acoustic Analyses

PURPOSE

Literature on apraxia of speech (AOS) in Chinese speakers is sparse compared to the English literature. This study aims to examine the pitch variation skills of Cantonese adults with AOS poststroke in terms of perceptual tone accuracy, acoustic fundamental frequency (fo) changes, and repetition durations on items with different syllable structures, lexical status, and tone syllables in various positions in a sequencing context.

METHOD

Six Cantonese adults with AOS poststroke (AOS group), six adults without AOS poststroke (nAOS group), and six healthy controls (HC group) performed the tone sequencing task (TST), which was adapted from oral diadochokinetic tasks, with three different tone syllables. Tone accuracy, fo values across 10 time points, and acoustic repetition durations were compared within and between the groups.

RESULTS

The AOS group produced significantly lower tone accuracy and different fo changes on the three Cantonese tone syllables compared with the control groups and significantly longer repetition durations than the HC group. The AOS group showed more difficulty with the tone syllables with the consonant-vowel structure, while a priming effect was observed on the T2 (high-rising) syllables with lexical meanings. A unique lowering of fo in the final syllable of the trisyllabic items was observed only in the AOS group.

CONCLUSIONS

The AOS group showed degraded pitch variation skills. The effects of the three linguistic elements were discussed. Future investigations are called for to adapt the TST in other tonal languages to determine if degraded pitch variation skills are present in other tonal language speakers with AOS.

Pitch Variation in Children With Childhood Apraxia of Speech: Preliminary Findings

Introduction Pitch variation, which refers to one's ability to vary fundamental frequency (F0) within or between syllables when speaking, has not been investigated in children with childhood apraxia of speech (CAS). However, pitch variation plays an important role in tone languages, as varying F0 patterns communicate different lexical meanings. This study investigated pitch variation abilities in individuals with CAS via the tone-sequencing tasks (TSTs), focusing on task performance and the effects of syllable structure, lexical status, and tones. Method Three Cantonese-speaking children with CAS (aged 3;7-5;8 [years;months]) and six children without CAS participated in the study. Children without CAS were divided into two control groups, comprising those with speech and/or language impairment or typical development. TSTs consisted of 56 sets of five repetitions of stimuli. The stimuli varied in syllable structure, lexical status, and tones. Percentage of tones correct (PTC), consistency scores, F0 values, and acoustic repetition duration were measured. Results The CAS group performed more poorly than the control groups on the TST with respect to tone accuracy, consistency, and repetition duration. No interaction effects between group and syllable structure or group and lexical status were found. No significant difference was found on F0 values across time between Tone 1 and Tone 2 syllables in the CAS group. However, interaction effects between group and time points of F0 values on Tone 2 syllables were found. Discussion The results suggest that children with CAS have difficulty with pitch variation, which was revealed on the TST with respect to tone accuracy, consistency, and repetition duration. Moreover, children with CAS have difficulty in varying F0 values to produce high-rising tones and tend to use high-level tones to substitute. Clinically, the TST may be useful to assist in the diagnosis of CAS. Isolated vowel stimuli may be useful to test young children or children with severe impairment. Future investigations and development of a normed tool for children with CAS are suggested.

The Influence of Tonal and Atonal Bilingualism on Children's Lexical and Non-Lexical Tone Perception

This study examined how bilingualism in an atonal language, in addition to a tonal language, influences lexical and non-lexical tone perception and word learning during childhood. Forty children aged 5;3-7;2, bilingual either in English and Mandarin or English and another atonal language, were tested on Mandarin lexical tone discrimination, level-pitch sine-wave tone discrimination, and learning of novel words differing minimally in Mandarin lexical tone. Mandarin-English bilingual children discriminated between and learned novel words differing minimally in Mandarin lexical tone more accurately than their atonal-English bilingual peers. However, Mandarin-English and atonal-English bilingual children discriminated between level-pitch sine-wave tones with similar accuracy. Moreover, atonal-English bilingual children showed a tendency to perceive differing Mandarin lexical and level-pitch sine-wave tones as identical, whereas their Mandarin-English peers showed no such tendency. These results indicate that bilingualism in a tonal language in addition to an atonal language-but not bilingualism in two atonal languages-allows for continued sensitivity to lexical tone beyond infancy. Moreover, they suggest that although tonal-atonal bilingualism does not enhance sensitivity to differences in pitch between sine-wave tones beyond infancy any more effectively than atonal-atonal bilingualism, it protects against the development of biases to perceive differing lexical and non-lexical tones as identical. Together, the results indicate that, beyond infancy, tonal-atonal bilinguals process lexical tones using different cognitive mechanisms than atonal-atonal bilinguals, but that both groups process level-pitch non-lexical tone using the same cognitive mechanisms.

Assessing the Link Between Perception and Production in Cantonese Tone Acquisition

Purpose Previous studies showed early production precedes late perception in Cantonese tone acquisition, contrary to the general principle that perception precedes production in child language. How tone production and perception are linked in 1st language acquisition remains largely unknown. Our study revisited the acquisition of tone in Cantonese-speaking children, exploring the possible link between production and perception in 1st language acquisition. Method One hundred eleven Cantonese-speaking children aged between 2;0 and 6;0 (years;months) and 10 adolescent reference speakers participated in tone production and perception experiments. Production materials with 30 monosyllabic words were transcribed in filtered and unfiltered conditions by 2 native judges. Perception accuracy was based on a 2-alternative forced-choice task with pictures covering all possible tone pair contrasts. Results Children's accuracy of production and perception of all the 6 Cantonese tones was still not adultlike by age 6;0. Both production and perception accuracies matured with age. A weak positive link was found between the 2 accuracies. Mother's native language contributed to children's production accuracy. Conclusions Our findings show that production and perception abilities are associated in tone acquisition. Further study is needed to explore factors affecting production accuracy in children. Supplemental Material https://doi.org/10.23641/asha.7960826.

Perception of Cantonese Lexical Tones by Pediatric Cochlear Implant Users

PURPOSE

The purpose of this study is to assess Cantonese word recognition and the discrimination of Cantonese tones with manipulated contours by child and adolescent cochlear implant (CI) users and a group of peers with normal hearing (NH). It was hypothesized that the CI users would perform more poorly than their counterparts with NH in both tasks and that CI users implanted before 2 years of age would perform better than those implanted after 2 years.

METHOD

Forty-one participants were recruited from hospitals, schools, and kindergartens in Hong Kong: Ten CI users implanted at or before 2 years of age ("early" CI group), 13 CI users implanted after 2 years of age ("late" CI group), and 18 individuals with NH. The mean age at implantation of the early CI group was 1.5 years (SD = 0.3), and for the late CI group, it was 4.3 years (SD = 2.1). Participants were a mean of 13.3 years of age (SD = 3.7) at time of testing. Participants completed a Cantonese word recognition test and a discrimination task using Cantonese tones with modified fundamental frequency trajectories.

RESULTS

Both CI user groups obtained significantly lower scores than the group with NH on the word recognition test. Mean percent correct scores for the word recognition test were 79% for the early CI group, 69% for the late CI group, and 97% for the group with NH. The group with NH consistently achieved higher scores than the CI user groups when discriminating manipulated Cantonese tones. Increasing the acoustic difference between tones improved discrimination performance for CI users for level tone contrasts only. CI users implanted at or before 2 years of age obtained higher scores than those implanted later.

CONCLUSIONS

The results of this study add further evidence that children using CIs do not perform as well as peers in perceiving Cantonese tones. Modification of tones to increase pitch range did not consistently improve the ability of children with implants to perceive the difference between tones. Further research is required to fully assess potential benefits of early implantation for speakers of tonal languages.

SUPPLEMENTAL MATERIALS

https://doi.org/10.23641/asha.5782209.

Applying Rasch model analysis in the development of the cantonese tone identification test (CANTIT)

OBJECTIVE

Applying Rasch analysis to evaluate the internal structure of a lexical tone perception test known as the Cantonese Tone Identification Test (CANTIT).

DESIGN

A 75-item pool (CANTIT-75) with pictures and sound tracks was developed. Respondents were required to make a four-alternative forced choice on each item. A short version of 30 items (CANTIT-30) was developed based on fit statistics, difficulty estimates, and content evaluation. Internal structure was evaluated by fit statistics and Rasch Factor Analysis (RFA).

STUDY SAMPLE

200 children with normal hearing and 141 children with hearing impairment were recruited.

RESULTS

For CANTIT-75, all infit and 97% of outfit values were < 2.0. RFA revealed 40.1% of total variance was explained by the Rasch measure. The first residual component explained 2.5% of total variance in an eigenvalue of 3.1. For CANTIT-30, all infit and outfit values were < 2.0. The Rasch measure explained 38.8% of total variance, the first residual component explained 3.9% of total variance in an eigenvalue of 1.9.

CONCLUSIONS

The Rasch model provides excellent guidance for the development of short forms. Both CANTIT-75 and CANTIT-30 possess satisfactory internal structure as a construct validity evidence in measuring the lexical tone identification ability of the Cantonese speakers.

An Application of Item Response Theory and the Rasch Model in Speech Recognition Test Materials

PURPOSE

The purpose of this study was to describe an attempt to apply item-response theory (IRT) and the Rasch model to construction of speech-recognition tests. A set of word-recognition test items applicable to children as young as 3 years old-with any level of hearing sensitivity, with or without using hearing devices-was developed.

METHOD

Test items were constructed through expert consultation and by reference to some established language corpora, validated with 121 participants with various degrees of hearing loss and 255 with typical hearing. IRT and the Rasch model were applied to evaluate item quality.

RESULTS

Eighty disyllabic word items were selected in accordance with IRT. The speech-recognition abilities of the 376 young participants are reported. The IRT analyses on this set of data are also discussed.

CONCLUSIONS

A new set of speech-recognition test materials in Cantonese Chinese has been developed. Construction of short equivalent lists may be performed in accordance with IRT item qualities. Clinical applications of this test tool in the particular language population are discussed.

Tune in to the Tone: Lexical Tone Identification is Associated with Vocabulary and Word Recognition Abilities in Young Chinese Children

Lexical tone is one of the most prominent features in the phonological representation of words in Chinese. However, little, if any, research to date has directly evaluated how young Chinese children's lexical tone identification skills contribute to vocabulary acquisition and character recognition. The present study distinguished lexical tones from segmental phonological awareness and morphological awareness in order to estimate the unique contribution of lexical tone in early vocabulary acquisition and character recognition. A sample of 199 Cantonese children aged 5-6 years was assessed on measures of lexical tone identification, segmental phonological awareness, morphological awareness, nonverbal ability, vocabulary knowledge, and Chinese character recognition. It was found that lexical tone awareness and morphological awareness were both associated with vocabulary knowledge and character recognition. However, there was a significant relationship between lexical tone awareness and both vocabulary knowledge and character recognition, even after controlling for the effects of age, nonverbal ability, segmental phonological awareness and morphological awareness. These findings suggest that lexical tone is a key factor accounting for individual variance in young children's lexical acquisition in Chinese, and that lexical tone should be considered in understanding how children learn new Chinese vocabulary words, in either oral or written forms.

A Tale of Two Features: Perception of Cantonese Lexical Tone and English Lexical Stress in Cantonese-English Bilinguals

This study investigated the similarities and differences in perception of Cantonese tones and English stress patterns by Cantonese-English bilingual children, adults, and English monolingual adults. All three groups were asked to discriminate pairs of syllables that minimally differed in either Cantonese tone or in English stress. Bilingual children’s performance on tone perception was comparable to their performance on stress perception. By contrast, bilingual adults’ performance on tone perception was lower than their performance on stress perception, and there was a similar pattern in English monolingual adults. Bilingual adults tended to perform better than English monolingual adults on both the tone and stress perception tests. A significant correlation between tone perception and stress perception performance was found in bilingual children but not in bilingual adults. All three groups showed lower accuracy in the high rising-low rising contrast than any of the other 14 Cantonese tone contrasts. The acoustic analyses revealed that average F0, F0 onset, and F0 major slope were the critical acoustic correlates of Cantonese tones, whereas multiple acoustic correlates were salient in English stress, including average F0, spectral balance, duration and intensity. We argue that participants’ difficulty in perceiving high rising-low rising contrasts originated from the contrasts’ similarities in F0 onset and average F0; indeed the difference between their major slopes was the only cue with which to distinguish them. Acoustic-perceptual correlation analyses showed that although the average F0 and F0 onset were associated with tone perception performance in all three groups, F0 major slope was only associated with tone perception in the bilingual adult group. These results support a dynamic interactive account of suprasegmental speech perception by emphasizing the positive prosodic transfer between Cantonese tone and English stress, and the role that level of bilingual language experience and age play in shaping suprasegmental speech perception.

A tale of two writing systems: double dissociation and metalinguistic transfer between Chinese and English word reading among Hong Kong children

This study investigated the rate of school-aged Chinese-English language learners at risk for reading difficulties in either Chinese or English only, or both, among second and fifth graders in Hong Kong. In addition, we examined the metalinguistic skills that distinguished those who were poor in reading Chinese from those who were poor in reading English. The prevalence of poor English readers among children identified to be poor in Chinese word recognition across the five participating schools was approximately 42% at Grade 2 and 57% at Grade 5. Across grades, children who were poor readers of both languages tended to have difficulties in phonological and morphological awareness. Poor readers of English only were found to manifest significantly poorer phonological awareness, compared to those who were poor readers of Chinese only; their average tone awareness score was also lower relative to normally developing controls. Apart from indicating possible dissociations between Chinese first language (L1) word reading and English second language (L2) word reading, these findings suggested that the degree to which different metalinguistic skills are important for reading in different writing systems may depend on the linguistic features of the particular writing system.

Lexical tone perception in native speakers of Cantonese

PURPOSE

This study aimed at investigating (1) tone perception development among typically-developing Cantonese speakers and (2) the hierarchy of tone perception difficulty among the 15 tone contrasts.

METHOD

Two-hundred typically-developing children aged 3-10 and a group of 25 normal hearing adults were recruited. They were tested on a pool of 75-item calibrated recorded speech signals. Participants responded to each stimulus by pointing at the corresponding picture displayed on a computer screen from a choice of four.

RESULT

There was a gradual increase in tone perception accuracy from children aged 3-6. After age 6, tone perception accuracy was similar to adults with an average error rate of 3-8%. The two tone contrasts that listeners consistently found difficult to distinguish were T2T5 (high-rising vs low-rising) and T3T6 (mid-level vs low-level). In addition, all children groups also showed difficulty in T4T6 identification (low-falling vs low-level).

CONCLUSION

Tone perception is not error-free even among native Cantonese-speaking adults. Overall tone identification performance improved steadily from age 3 to age 6. Based on the participants' performance, a three-tier set of tone groups, with an increasing level of difficulty for identification, is proposed for rehabilitation purposes. These tone groups are (1) Easy: T1T2, T1T3, T1T4, T1T5, T1T6, and T2T3, (2) Medium: T2T4, T2T6, T3T4, and T4T5, and (3) Hard: T2T5, T3T5, T3T6, T4T6, and T5T6.

Cantonese tone production performance of mainstream school children with hearing impairment

This study investigated the Cantonese tone production ability of children with hearing impairment studying in mainstream schools. The participants were 87 Cantonese-speaking children with mild-to-profound degrees of hearing loss aged 5.92-13.58 in Hong Kong. Most of the children were fitted with hearing aids (n = 65); 17 of them had profound hearing impairment, one who had severe hearing loss had cochlear implantation, and four who had mild hearing loss were without any hearing device. The Hong Kong Cantonese Articulation Test was administered, and the tones produced were rated by two of the authors and a speech-language pathologist. Group effects of tones, hearing loss level, and also an interaction of the two were found to be significant. The children with profound hearing impairment performed significantly worse than most of the other children. Tone 1 was produced most accurately, whereas tone 6 productions were the poorest. No relationship was found between the number of years of mainstreaming and tone production ability. Tone production error pattern revealed that confusion patterns in tone perception coincided with those in production. Tones having a similar fundamental frequency (F0) at the onset also posed difficulty in tone production for children with hearing impairment.

Development and validation of a new Mandarin tone identification test

OBJECTIVES

The objectives of this study were to develop a new Mandarin tone identification test (MTIT) to assess the Mandarin tone identification ability of children with hearing impairment (HI) and at age around 7 years; and to evaluate the reliability and sensitivity of the MTIT.

METHODS

The word materials to be used in the MTIT were developed in Phase I. Monosyllables were chosen to represent the daily repertoire of young children and to avoid the influence of co-articulation and intonation. Each test stimulus set contained four words, with one target, one containing contrastive tone, and two unrelated distracters. All words were depicted using simple pictures, and the test targets in quiet or in noise were presented using recorded stimuli on a custom software. Phase II evaluated the reliability and sensitivity of the MTIT. Participants were 50 normal-hearing native-Mandarin speakers around 7 years of age.

RESULTS

In Phase I, the MTIT was developed as described above. The final test consists of 51 words that are within the vocabulary repertoire of children aged 7 years. In Phase II, with the Mandarin tone identification scores collected from 50 children, the repeated measure ANOVA showed a significant main effect of S/N on MTIT performance (p<0.001). Pairwise comparisons revealed a significant difference in performance across the five S/N conditions (p<0.01) when S/N varied from -30 to -10dB. Cronbach's alpha at -15dB S/N was 0.66, suggesting satisfactory internal consistency reliability. A paired-samples t-test showed that there was no significant difference between the test-retest scores across the five S/N conditions (p>0.05).

CONCLUSIONS

Compared with the available Mandarin tone identification tools, MTIT systematically evaluated the tone identification performance in noisy environment for normal hearing children at age around 7 years. Results also showed satisfactory internal consistency reliability, good test-retest reliability and good sensitivity. In the near future, MTIT could be used to evaluate tone perception ability of children with hearing impairment and help to design hearing rehabilitation strategies for this population at the age critical for their language learning.

Cues for lexical tone perception in children: acoustic correlates and phonetic context effects

PURPOSE

The authors investigated the effects of acoustic cues (i.e., pitch height, pitch contour, and pitch onset and offset) and phonetic context cues (i.e., syllable onsets and rimes) on lexical tone perception in Cantonese-speaking children.

METHOD

Eight minimum pairs of tonal contrasts were presented in either an identical phonetic context or in different phonetic contexts (different syllable onsets and rimes). Children were instructed to engage in tone identification and tone discrimination.

RESULTS

Cantonese children attended to pitch onset in perceiving similarly contoured tones and attended to pitch contour in perceiving different-contoured tones. There was a decreasing level of tone discrimination accuracy, with tone perception being easiest for same rime-different syllable onset, more difficult for different rime-same syllable onset, and most difficult for different rime-different syllable onset phonetic contexts. This pattern was observed in tonal contrasts in which the member tones had the same contour but not in ones in which the member tones had different contours.

CONCLUSION

These findings suggest that in addition to pitch contour, the pitch onset is another important acoustic cue for tone perception. The relative importance of acoustic cues for tone perception is phonetically context dependent. These findings are discussed with reference to a newly modified TRACE model for tone languages (TTRACE).

Cantonese tone recognition with enhanced temporal periodicity cues

This study investigated the contributions of temporal periodicity cues and the effectiveness of enhancing these cues for Cantonese tone recognition in noise. A multichannel noise-excited vocoder was used to simulate speech processing in cochlear implants. Ten normal-hearing listeners were tested. Temporal envelope and periodicity cues (TEPCs) below 500 Hz were extracted from four frequency bands: 60-500, 500-1000, 1000-2000, and 2000-4000 Hz. The test stimuli were obtained by combining TEPC-modulated noise signals from individual bands. For periodicity enhancement, temporal fluctuations in the range 20-500 Hz were replaced by a sinusoid with frequency equal to the fundamental frequency of original speech. Tone identification experiments were carried out using disyllabic word carriers. Results showed that TEPCs from the two high-frequency bands were more important for tone identification than TEPCs from the low-frequency bands. The use of periodicity-enhanced TEPCs led to consistent improvement of tone identification accuracy. The improvement was more significant at low signal-to-noise ratios, and more noticeable for female than for male voices. Analysis of error distributions showed that the enhancement method reduced tone identification errors and did not show any negative effect on the recognition of segmental structures.

Perception of tone and aspiration contrasts in Chinese children with dyslexia

BACKGROUND

Previous research has shown a relationship between speech perception and dyslexia in alphabetic writing. In these studies speech perception was measured using phonemes, a prominent feature of alphabetic languages. Given the primary importance of lexical tone in Chinese language processing, we tested the extent to which lexical tone and aspiration, two fundamental dimensions of Cantonese speech not represented in writing, would distinguish dyslexic from non-dyslexic 8-year-old Chinese children. Tone and aspiration were tested in addition to other phonological processing skills across groups to determine the importance of different aspects of phonological sensitivity in relation to reading disability.

METHODS

Dyslexic children and age-matched and reading-level controls were tested on their categorical perception of minimal pairs contrasting in tone and aspiration, phonological awareness, rapid digit naming, and Chinese reading abilities.

RESULTS

While performing similarly to reading-level controls, dyslexic children perceived tone and aspiration contrasts less categorically and accurately than age-matched controls. They also performed more poorly than the age-matched controls on rapid digit naming and a measure of phonological awareness testing children's sensitivity to different grain size units.

CONCLUSIONS

Dyslexia in non-alphabetic Chinese correlates with the categorical organization and accuracy of Cantonese speech perception, along the tone and aspiration dimensions. This association with reading is mediated by its association with phonological awareness. Therefore, dyslexia is universally at least partly a function of basic speech and phonological processes independent of whether the speech dimensions in question are coded in writing.

Development of the Cantonese speech intelligibility index

A Speech Intelligibility Index (SII) for the sentences in the Cantonese version of the Hearing In Noise Test (CHINT) was derived using conventional procedures described previously in studies such as Studebaker and Sherbecoe [J. Speech Hear. Res. 34, 427-438 (1991)]. Two studies were conducted to determine the signal-to-noise ratios and high- and low-pass filtering conditions that should be used and to measure speech intelligibility in these conditions. Normal hearing subjects listened to the sentences presented in speech-spectrum shaped noise. Compared to other English speech assessment materials such as the English Hearing In Noise Test [Nilsson et al., J. Acoust. Soc. Am. 95, 1085-1099 (1994)], the frequency importance function of the CHINT suggests that low-frequency information is more important for Cantonese speech understanding. The difference in ,frequency importance weight in Chinese, compared to English, was attributed to the redundancy of test material, tonal nature of the Cantonese language, or a combination of these factors.