Categorical Perception Of Lexical Tones Research Articles

Categorical Perception of Lexical Tones and Stops in Mandarin-Speaking Musicians and Nonmusicians

This study investigates the perception of Mandarin lexical tones and stops to examine the degree of overlap between music and language. Eighteen musicians and 21 nonmusicians participated in a typical categorical perception task. Results showed that musicians and nonmusicians had comparable degree of categorical perception of tones and stops. Compared to nonmusicians, musicians exhibited enhanced sensitivities to within-category lexical tone stimuli. However, this improved ability was not observed in the perception of stops. These findings imply that musical experience strengthens the acuity of subtle low-level acoustic variations between within-category lexical tone stimuli without interfering with the high-level phonological representations of lexical tones, and this facilitatory effect is selective and could not readily extend to stop consonants in native language.

Sustainable Benefits of High Variability Phonetic Training in Mandarin-speaking Kindergarteners With Cochlear Implants: Evidence From Categorical Perception of Lexical Tones.

Although pitch reception poses a great challenge for individuals with cochlear implants (CIs), formal auditory training (e.g., high variability phonetic training [HVPT]) has been shown to provide direct benefits in pitch-related perceptual performances such as lexical tone recognition for CI users. As lexical tones in spoken language are expressed with a multitude of distinct spectral, temporal, and intensity cues, it is important to determine the sources of training benefits for CI users. The purpose of the present study was to conduct a rigorous fine-scale evaluation with the categorical perception (CP) paradigm to control the acoustic parameters and test the efficacy and sustainability of HVPT for Mandarin-speaking pediatric CI recipients. The main hypothesis was that HVPT-induced perceptual learning would greatly enhance CI users' ability to extract the primary pitch contours from spoken words for lexical tone identification and discrimination. Furthermore, individual differences in immediate and long-term gains from training would likely be attributable to baseline performance and duration of CI use. Twenty-eight prelingually deaf Mandarin-speaking kindergarteners with CIs were tested. Half of them received five sessions of HVPT within a period of 3 weeks. The other half served as control who did not receive the formal training. Two classical CP tasks on a tonal continuum from Mandarin tone 1 (high-flat in pitch) to tone 2 (mid-rising in pitch) with fixed acoustic features of duration and intensity were administered before (pretest), immediately after (posttest), and 10 weeks posttraining termination (follow-up test). Participants were instructed to either label a speech stimulus along the continuum (i.e., identification task) or determine whether a pair of stimuli separated by zero or two steps from the continuum was the same or different (i.e., discrimination task). Identification function measures (i.e., boundary position and boundary width) and discrimination function scores (i.e., between-category score, within-category score, and peakedness score) were assessed for each child participant across the three test sessions. Linear mixed-effects (LME) models showed significant training-induced enhancement in lexical tone categorization with significantly narrower boundary width and better between-category discrimination in the immediate posttest over pretest for the trainees. Furthermore, training-induced gains were reliably retained in the follow-up test 10 weeks after training. By contrast, no significant changes were found in the control group across sessions. Regression analysis confirmed that baseline performance (i.e., boundary width in the pretest session) and duration of CI use were significant predictors for the magnitude of training-induced benefits. The stringent CP tests with synthesized stimuli that excluded acoustic cues other than the pitch contour and were never used in training showed strong evidence for the efficacy of HVPT in yielding immediate and sustained improvement in lexical tone categorization for Mandarin-speaking children with CIs. The training results and individual differences have remarkable implications for developing personalized computer-based short-term HVPT protocols that may have sustainable long-term benefits for aural rehabilitation in this clinical population.

Categorical perception of lexical tones in Chinese people with post-stroke aphasia

ABSTRACT This study used the categorical perception (CP) paradigm, a fine-grained perceptual method, to investigate the perceptual performance of lexical tones in Chinese people with post-stroke aphasia (PWA). Twenty patients with post-stroke aphasia (10 Broca’s and 10 Wernicke’s) and ten neurologically intact age-matched control participants were recruited to complete both identification and discrimination tasks of the Mandarin Tone 1–2 continuum. In addition, all participants completed tests on their auditory comprehension ability and working memory. The results showed that both Broca’s and Wernicke’s patients exhibited reduced sensitivity to within-category and between-category information but preserved CP of lexical tones. The degree of CP of lexical tones related to working memory in aphasic patients. Furthermore, lower-level acoustic processing underpinned higher-level phonological processing on the CP of lexical tones since both patient groups’ unbalanced pitch processing ability extended to their CP of lexical tones. These findings are significant for researchers and clinicians in speech-language rehabilitation, clinical psychology, and cognitive communication.

Late mismatch negativity of lexical tone at age 8 predicts Chinese children's reading ability at age 10.

Deficits in phonological processing are commonly reported in dyslexia but longitudinal evidence that poor speech perception compromises reading is scant. This 2-year longitudinal ERP study investigates changes in pre-attentive auditory processing that underlies categorical perception of mandarin lexical tones during the years children learn to read fluently. The main purpose of the present study was to explore the development of lexical tone categorical perception to see if it can predict children's reading ability. Both behavioral and electrophysiological measures were taken in this study. Auditory event-related potentials were collected with a passive listening oddball paradigm. Using a stimulus continuum spanning from one lexical tone category exemplar to another, we identified a between-category and a within-category tone deviant that were acoustically equidistant from a standard stimulus. The standard stimulus occurred on 80% of trials, and one of two deviants (between-category or within-category) equiprobably on the remaining trials. 8-year-old Mandarin speakers participated in both an initial ERP oddball paradigm and returned for a 2-year follow-up. The between-category MMN and within-category MMN significantly correlate with each other at age 8 (p = 0.001) but not at age 10. The between-category MMN at age 8 can predict children's ability at age 10 (p = 0.03) but the within-category cannot. The categorical perception of lexical tone is still developing from age 8 to age 10. The behavioral and electrophysiological results demonstrate that categorical perception of lexical tone at age 8 predicts children's reading ability at age 10.

Categorical Perception of Lexical Tones in Mandarin-Speaking Seniors.

This study aims to investigate the different degeneration processes of categorical perception (CP) of Mandarin lexical tones in the normal aging population and the pathological aging population with mild cognitive impairment (MCI). In Experiment I, we compared the identification and discrimination of Tone 1 and Tone 2 across young adults, seniors aged 60-65 years, and older seniors aged 75-80 years with normal cognitive abilities. In Experiment II, we compared lexical tone identification and discrimination across young adults, healthy seniors, and age-matched seniors with MCI. In Experiment I, tone perception was intact in seniors aged below 65 years. Those aged above 75 years could also maintain normal tone identification, whereas they showed poorer tone discrimination correlated with age-related poorer hearing level. In Experiment II, healthy seniors showed normal CP of Mandarin tones. Tone identification was also normal in those with MCI, whereas their tone discrimination had significantly degenerated. In the normal aging population, age-related hearing loss decreased signal audibility, accounting for poorer discrimination of Mandarin lexical tones in seniors above 75 years. In the pathological aging population with MCI, the poorer discrimination of lexical tones may be attributed to the additive effect of age, hearing loss, and cognitive impairment (e.g., impaired working memory and long-term phonological memory). This study uncovered the roles of low-level sensory processing and high-level cognitive processing in lexical tone perception in the Chinese aging population.

Categorical Perception of Chinese Lexical Tones by Late Second Language Learners With High Proficiency: Behavioral and Electrophysiological Measures.

Although acquisition of Chinese lexical tones by second language (L2) learners has been intensively investigated, very few studies focused on categorical perception (CP) of lexical tones by highly proficient L2 learners. This study was designed to address this issue with behavioral and electrophysiological measures. Behavioral identification and auditory event-related potential (ERP) components for speech discrimination, including mismatch negativity (MMN), N2b, and P3b, were measured in 23 native Korean speakers who were highly proficient late L2 learners of Chinese. For the ERP measures, both passive and active listening tasks were administered to examine the automatic and attention-controlled discriminative responses to within- and across-category differences for carefully chosen stimuli from a lexical tone continuum. The behavioral task revealed native-like identification function of the tonal continuum. Correspondingly, the active oddball task demonstrated larger P3b amplitudes for the across-category than within-category deviants in the left recording site, indicating clear CP of lexical tones in the attentive condition. By contrast, similar MMN responses in the right recording site were elicited by both the across- and within-category deviants, indicating the absence of CP effect with automatic phonological processing of lexical tones at the pre-attentive stage even in L2 learners with high Chinese proficiency. Although behavioral data showed clear evidence of categorical perception of lexical tones in proficient L2 learners, ERP measures from passive and active listening tasks demonstrated fine-grained sensitivity in terms of response polarity, latency, and laterality in revealing different aspects of auditory versus linguistic processing associated with speech decoding by means of largely implicit native language acquisition versus effortful explicit L2 learning.

Categorical perception of lexical tones based on acoustic-electric stimulation.

The effect of low-frequency acoustic input on the categorical perception of lexical tones was investigated with simulated electric-acoustic hearing. A synthesized T1-T2 (flat-rising) tone continuum of Mandarin monosyllables /i/ was used, and they were manipulated as five conditions: unprocessed, low-frequency acoustic-only, electric-only, electric-acoustic stimulation, and bimodal stimulation. Results showed the performance under electric-only condition was the significantly lowest, and the difference of other pairwise comparisons between conditions was quite small. These findings suggest that the low-frequency acoustic input can shape the categorical perception, and the combinations of acoustic and electric hearing within or across ears have no significant effect.

Effects of Amateur Musical Experience on Categorical Perception of Lexical Tones by Native Chinese Adults: An ERP Study.

Music impacting on speech processing is vividly evidenced in most reports involving professional musicians, while the question of whether the facilitative effects of music are limited to experts or may extend to amateurs remains to be resolved. Previous research has suggested that analogous to language experience, musicianship also modulates lexical tone perception but the influence of amateur musical experience in adulthood is poorly understood. Furthermore, little is known about how acoustic information and phonological information of lexical tones are processed by amateur musicians. This study aimed to provide neural evidence of cortical plasticity by examining categorical perception of lexical tones in Chinese adults with amateur musical experience relative to the non-musician counterparts. Fifteen adult Chinese amateur musicians and an equal number of non-musicians participated in an event-related potential (ERP) experiment. Their mismatch negativities (MMNs) to lexical tones from Mandarin Tone 2–Tone 4 continuum and non-speech tone analogs were measured. It was hypothesized that amateur musicians would exhibit different MMNs to their non-musician counterparts in processing two aspects of information in lexical tones. Results showed that the MMN mean amplitude evoked by within-category deviants was significantly larger for amateur musicians than non-musicians regardless of speech or non-speech condition. This implies the strengthened processing of acoustic information by adult amateur musicians without the need of focused attention, as the detection of subtle acoustic nuances of pitch was measurably improved. In addition, the MMN peak latency elicited by across-category deviants was significantly shorter than that by within-category deviants for both groups, indicative of the earlier processing of phonological information than acoustic information of lexical tones at the pre-attentive stage. The results mentioned above suggest that cortical plasticity can still be induced in adulthood, hence non-musicians should be defined more strictly than before. Besides, the current study enlarges the population demonstrating the beneficial effects of musical experience on perceptual and cognitive functions, namely, the effects of enhanced speech processing from music are not confined to a small group of experts but extend to a large population of amateurs.

Bimodal Benefits Revealed by Categorical Perception of Lexical Tones in Mandarin-Speaking Kindergarteners With a Cochlear Implant and a Contralateral Hearing Aid.

Purpose Pitch reception poses challenges for individuals with cochlear implants (CIs), and adding a hearing aid (HA) in the nonimplanted ear is potentially beneficial. The current study used fine-scale synthetic speech stimuli to investigate the bimodal benefit for lexical tone categorization in Mandarin-speaking kindergarteners using a CI and an HA in opposite ears. Method The data were collected from 16 participants who were required to complete two classical tasks for speech categorical perception (CP) with CI + HA device condition and CI alone condition. Linear mixed-effects models were constructed to evaluate the identification and discrimination scores across different device conditions. Results The bimodal kindergarteners showed CP for the continuum varying from Mandarin Tone 1 and Tone 2. Moreover, the additional acoustic information from the contralateral HA contributes to improved lexical tone categorization, with a steeper slope, a higher discrimination score of between-category stimuli pair, and an improved peakedness score (i.e., an increased benefit magnitude for discriminations of between-category over within-category pairs) for the CI + HA condition than the CI alone condition. The bimodal kindergarteners with better residual hearing thresholds at 250 Hz level in the nonimplanted ear could perceive lexical tones more categorically. Conclusion The enhanced CP results with bimodal listening provide clear evidence for the clinical practice to fit a contralateral HA in the nonimplanted ear in kindergarteners with unilateral CIs with direct benefits from the low-frequency acoustic hearing.

Reduced Sensitivity to Between-Category Information but Preserved Categorical Perception of Lexical Tones in Tone Language Speakers With Congenital Amusia.

Previous studies have shown that for congenital amusics, long-term tone language experience cannot compensate for lexical tone processing difficulties. However, it is still unknown whether such difficulties are merely caused by domain-transferred insensitivity in lower-level acoustic processing and/or by higher-level phonological processing of linguistic pitch as well. The current P300 study links and extends previous studies by uncovering the neurophysiological mechanisms underpinning lexical tone perception difficulties in Mandarin-speaking amusics. Both the behavioral index (d′) and P300 amplitude showed reduced within-category as well as between-category sensitivity among the Mandarin-speaking amusics regardless of the linguistic status of the signal. The results suggest that acoustic pitch processing difficulties in amusics are manifested profoundly and further persist into the higher-level phonological processing that involves the neural processing of different lexical tone categories. Our findings indicate that long-term tone language experience may not compensate for the reduced acoustic pitch processing in tone language speakers with amusia but rather may extend to the neural processing of the phonological information of lexical tones during the attentive stage. However, from both the behavioral and neural evidence, the peakedness scores of the d′ and P300 amplitude were comparable between amusics and controls. It seems that the basic categorical perception (CP) pattern of native lexical tones is preserved in Mandarin-speaking amusics, indicating that they may have normal or near normal long-term categorical memory.

Evidence of both brainstem and auditory cortex involvement in categorical perception for Chinese lexical tones.

The categorical perception of lexical tones is important to understand tonal languages. Recent studies have provided electrophysiological evidence for the categorical perception of lexical tones at the cortical level; however, whether neural correlates exist at subcortical levels remain unknown. In this study, by using across-category and within-category lexical tone contrasts with the equivalent physical interval, we recorded deviance detection activities at both the brainstem (reflected by frequency following response) and cortical levels (reflected by mismatch negativity) simultaneously. We found that significantly enhanced intertrial phase-locking of frequency following response s was observed only during the across-category deviance detection, which indicates that phonological differences could be detected at the level of brainstem. In addition, the across-category deviants induced stronger mismatch negativity than within-category deviants. For the first time, our results demonstrate that neural correlates of categorical perception of lexical tones exist even in the brainstem, and suggests that both cortical and subcortical processes are involved in the coding and categorization of tonal information.

Developmental changes in categorical perception of Mandarin Chinese tones

This study examined developmental changes in categorical perception of Mandarin Chinese lexical tones by 22 adults and 16 10-year-olds, who were all native Mandarin Chinese speakers. The speech stimuli included three types of continuum, tone 1 (T1)/tone 2 (T2), tone 1/tone 4 (T4) and tone 2/tone 4. The experimental protocol used conventional identification and discrimination tasks. The results confirmed categorical perception of the tonal continua by both adult and child groups. Refined tests further revealed the existence of T1 category with two phonetic boundaries in the T2/T4 continuum. More importantly, age-dependent differences were observed in discrimination accuracy and sensitivity to pitch height. Collectively, the data suggest that although adult-like categorical perception of lexical tones can be found by 10 years of age and earlier as the literature suggested, the dynamic developmental trajectory in fine-tuning the categorical perception of lexical tones extends beyond the age of 10.

Influence of L1 Background on Categorical Perception of Mandarin Tones by Russian and Vietnamese Listeners

This study investigated the influence of L1 background on categorical perception of lexical tones by three language groups, namely native Mandarin, Russian and Vietnamese listeners. Tone identification and discrimination scores of two tone continua (T1-T2 and T1-T4) were measured for each participant. Results showed that the two tone language groups, i.e., Mandarin and Vietnamese listeners, perceived both tone continua categorically whereas the non-tone language group, i.e., Russian listeners, did not. More specifically, while the Russian group exhibited significantly broader identification boundaries and performed near chance level in discrimination tasks, the Mandarin and Vietnamese groups presented sharp slopes in identification curves and corresponding discrimination peaks at the cross-boundary positions. Moreover, Mandarin and Vietnamese listeners showed slightly different discrimination curves, which could be attributed to the effect of their different tone inventories. The current findings suggest that native tone language background, to some extent, can facilitate non-native tone perception.

Categorical perception of lexical tones in native Mandarin-speaking listeners with sensorineural hearing loss

Background: Categorical perception (CP) of lexical tones was examined in normal hearing (NH) people, but it was unclear whether lexical tones can be perceived categorically in sensorineural hearing loss (SNHL) people.Objectives: To explore the characteristic of lexical tone perception in native Mandarin speakers with SNHL.Materials and methods: Three types of continuum (Tone1/Tone2, Tone1/Tone4 and Tone2/Tone3) were constructed and each of them includes 15 stimuli which were resynthesized by applying the pitch-synchronous overlap and add (PSOLA) method implemented in Praat to the same Mandarin syllable, /a/, with a high-level tone produced by a female speaker. Forty native Mandarin NH speakers and 23 native Mandarin speakers with mild to moderate SNHL were recruited. A two alternative-forced-choice identification task was used to acquire the tonal perceptual data.Results: All tone perception curves owns the characteristic of CP in SNHL subjects. All tone perception curves were S-shape in SNHL subjects same as those in NH subjects. No significant difference of each continuum was observed between SNHL and NH.Conclusions: CP of lexical tone perception could be observed in native Mandarin speakers with mild to moderate SNHL. The slight damage in the peripheral auditory system did not change characteristic of lexical tone perception.

Electrophysiological correlates of categorical perception of lexical tones by English learners of Mandarin Chinese: an ERP study

This study examines brain responses to boundary effects with respect to Mandarin lexicaltonecontinua for three groups of adult listeners: (1) native English speakers who took advanced Mandarin courses; (2) naïve English speakers; and (3) native Mandarin speakers. A cross-boundary tone pair and a within-category tone pair derived from tonal contrasts(Mandarin Tone1/Tone 4;Tone2/Tone 3) with equal physical/acoustical distance were used in an auditory oddball paradigm. For native Mandarin speakers, the cross-category deviant elicited a larger MMN over left hemisphere sensors and larger P300 responses over both hemispheres relative to within-category deviants, suggesting categorical perception of tones at both pre-attentive and attentional stages of processing. In contrast, native English speakers and Mandarin learners did not demonstrate categorical effects. However, learners of Mandarin showed larger P300 responses than the other two groups, suggesting heightened sensitivity to tones and possibly greater attentional resource allocation to tone identification.

How within-category gradience in lexical tones influences native Chinese listeners and second-language Chinese learners recognize words: An eye-tracking study

This study investigates whether within-category gradience in lexical tones influences native and non-native Chinese listeners’ word recognition. Previous offline research found that Chinese listeners have a more categorical perception of lexical tones, and thus show less sensitivity to within-category variability in tones, than non-native listeners. However, it is unclear whether native and non-native listeners have sensitivity to within-category gradience during online word recognition. Native Chinese listeners and proficient adult English-speaking Chinese learners were tested in a visual-world eye-tracking experiment. The target was a level tone and the competitor was a high-rising tone, or vice versa. The auditory stimuli were manipulated such that the target tone was either canonical in the standard condition, phonetically more distant from the competitor in the distant condition, or phonetically closer to the competitor in the close condition. Growth curve analysis on fixations suggested that native ...

Speech-specific categorical perception deficit in autism: An Event-Related Potential study of lexical tone processing in Mandarin-speaking children

Recent studies reveal that tonal language speakers with autism have enhanced neural sensitivity to pitch changes in nonspeech stimuli but not to lexical tone contrasts in their native language. The present ERP study investigated whether the distinct pitch processing pattern for speech and nonspeech stimuli in autism was due to a speech-specific deficit in categorical perception of lexical tones. A passive oddball paradigm was adopted to examine two groups (16 in the autism group and 15 in the control group) of Chinese children’s Mismatch Responses (MMRs) to equivalent pitch deviations representing within-category and between-category differences in speech and nonspeech contexts. To further examine group-level differences in the MMRs to categorical perception of speech/nonspeech stimuli or lack thereof, neural oscillatory activities at the single trial level were further calculated with the inter-trial phase coherence (ITPC) measure for the theta and beta frequency bands. The MMR and ITPC data from the children with autism showed evidence for lack of categorical perception in the lexical tone condition. In view of the important role of lexical tones in acquiring a tonal language, the results point to the necessity of early intervention for the individuals with autism who show such a speech-specific categorical perception deficit.

Categorical perception of lexical tones by English learners of Mandarin Chinese.

Whether native speakers of non-tonal languages can acquire categorical representations of lexical tones remains controversial. This study investigates the acquisition of lexical tone categories by native English speakers learning Mandarin Chinese as a foreign language by comparing the categorical perception (CP) of lexical tones between three groups of listeners: (1) native English speakers who had taken advanced Mandarin courses in colleges; (2) native English speakers with no knowledge of Mandarin Chinese; and (3) native Mandarin speakers. Two tonal continua derived from natural speech within carrier phrases were created through interpolation within two tonal contrasts (tone 1/tone 4, T1/T4; tone 2/tone 3, T2/T3). Results showed categorical-like perception of tones by native Mandarin speakers. The inexperienced English speakers performed near chance on discrimination tasks and showed significantly broader identification boundaries than the other two groups. The learners of Mandarin showed similar pattern of CP to native Mandarin speakers, but with higher overall discrimination scores. Findings suggest that CP of lexical tone may be available to advanced second language learners.

Aging effect on categorical perception of Mandarin level-rising and level-falling tones

The primary purpose of the study was to investigate the aging effect on categorical perception of Mandarin Chinese tone 1 (level F0 pitch contour) and tone 2 (rising F0 pitch contour), as well as tone 1 and tone 4 (falling F0 pitch contour). Using level/rising and level/falling fundamental frequency continuum, both tone identification and discrimination was measured for older and younger native Mandarin listeners. Moreover, the stimuli duration was manipulated at 100, 200, and 400 ms with a purpose to examine whether longer duration made tone perception easier for the older listeners. Results reported reduced catgoricality in terms of shallower identification slope and smaller discrimination peakedness for the older listeners compared with their younger counterparts. Meanwhile, longer duration was observed with enhanced categorical perception of lexical tones for the older listeners. These results were interpreted as the decline of aging-related temporal/spectral processing and inhibitory control in the central auditory system.

Categorical perception of lexical tones in mandarin-speaking congenital amusics.

Previous research suggests that within Mandarin-speaking congenital amusics, only a subgroup has behavioral lexical tone perception impairments (tone agnosia), whereas the rest of amusics do not. The purpose of the current study was to investigate the categorical nature of lexical tone perception in Mandarin-speaking amusics with and without behavioral lexical tone deficits. Three groups of listeners (controls, pure amusics, and amusics with tone agnosia) participated in tone identification and discrimination tasks. Indexes of the categorical perception (CP) of a physical continuum of fundamental frequencies ranging from a rising to level tone were measured. Specifically, the stimulus durations were manipulated at 100 and 200 ms. For both stimulus durations, all groups exhibited similar categorical boundaries. The pure amusics showed sharp identification slopes and significantly peaked discrimination functions similar to those of normal controls. However, such essential characteristics for the CP of lexical tones were not observed in amusics with tone agnosia. An enlarged step-size from 20 to 35 Hz was not able to produce any discrimination peaks in tone agnosics either. The current study revealed that only amusics with tone agnosia showed a lack of categorical tone perception, while the pure amusics demonstrated typical CP of lexical tones, indicating that the deficit of pitch processing in music does not necessarily result in the deficit in the CP of lexical tones. The different performance between congenital amusics with and without tone agnosia provides a new perspective on the proposition of the relationship between music and speech perception.