Non-native Tone Research Articles

PHONETIC INFLUENCES ON ENGLISH AND FRENCH LISTENERS’ ASSIMILATION OF MANDARIN TONES TO NATIVE PROSODIC CATEGORIES

This study examined how native speakers of Australian English and French, nontone languages with different lexical stress properties, perceived Mandarin tones in a sentence environment according to their native sentence intonation categories (i-Categories) in connected speech. Results showed that both English and French speakers categorized Mandarin tones primarily on the phonetic similarities of the pitch contours between the Mandarin tones and their native i-Categories. Moreover, French but not English speakers were able to detect the fine-detailed phonetic differences between Tone 3 (T3) and Tone 4 (T4; i.e., low or low-falling tone vs. high-falling tone), which suggests that the stress differences between these languages may affect nonnative tone perception: English uses lexical stress, whereas French does not. In the discrimination task, the French listeners’ performance was better than that of the English listeners. For each group, discrimination of the Tone 1 (T1)–T4 and Tone 2 (T2)–T3 pairs was consistently and significantly lower than that of the other tone pairs, and the difference between T1-T4 and T2-T3 was significant. Discrimination of the Mandarin tone pairs was not fully predicted by pairwise categorizations to native i-Categories, however. Some discrimination differences were observed among tone pairs showing the same assimilation patterns. Phonetic overlaps in native i-Category choices for the Mandarin tones, strength of categorization (So, 2012), and tonal coarticulation effects (Xu, 1994, 1997) may offer possible accounts of these discrepancies between categorization and discrimination performance. These findings support the perceptual assimilation model for suprasegmentals (So & Best, 2008, 2010a, 2010b, 2011, 2013), extended to categorization of nonnative tone words within sentence contexts to native i-Categories.

Lexical function of pitch in the first language shapes cross-linguistic perception of Thai tones

AbstractDetermining the factors involved in the non-native perception of the pitch patterns of tones is complicated by the fact that all languages use pitch to various extents, whether linguistic (e.g., intonation) or non-linguistic (e.g., singing). Moreover, many languages use pitch to distinguish lexical items with varying degrees of functional load and differences in inventory of such pitch patterns. The current study attempts to understand what factors determine accurate naïve (= non-learner) perception of non-native tones, in order to establish the baseline for acquisition of a tonal L2. We examine the perception of Thai tones (i.e., three level tones, two contour tones) by speakers of languages on a spectrum of lexically contrastive pitch usage: Mandarin (lexical tone), Japanese (lexical pitch accent), English (lexical stress), and Korean (no lexically contrastive pitch). Results suggest that the importance of lexically contrastive pitch in the L1 influences non-native tone perception so that not all non-tonal language speakers possess the same level of tonal sensitivity, resulting in a hierarchy of perceptual accuracy. Referencing the Feature Hypothesis (McAllister et al. 2002), we propose the Functional Pitch Hypothesis to model our findings: the degree to which linguistic pitch differentiates lexical items in the L1 shapes the naïve perception of a non-native lexically contrastive pitch system, e.g., tones.

The perception of Mandarin lexical tones by native Japanese and Thai listeners

Mandarin differentiates four tones (T1: high level (ā), T2: high rising (a), T3: dipping (ǎ), T4: high falling (a)). Learning these lexical tones is known to be difficult for those from non-tonal language background (e.g., English). What about listeners with no knowledge of Mandarin but have varying experience with tones or pitch variation? This study examined the discrimination of 6 Mandarin tone contrasts (T1-T2, T1-T3, T1-T4, T2-T3, T2-T4, and T3-T4) by native speakers of Japanese (pitch-accent language) and Thai (tonal language). The listeners’ tone discrimination accuracy was assessed in a categorical discrimination test developed by Jim Flege and colleagues. Both non-native groups were less accurate than the native group, in particular, for the T1-T2, T1-T3, T1-T4, and T2-T3 contrasts. Despite using lexical tones in their first language (L1), Thai listeners did not have a distinct advantage over Japanese listeners and the two groups showed a similar pattern of results. Overall, discrimination accuracy of contrasts involving T1 was lower than other contrasts with the exception of T2-T3. Both Japanese and Thai listeners had greatest difficulty with T2-T3. Since previous knowledge of L1 tones may interfere with the perception of non-native tones, these results will be discussed with reference to a Thai tonal system.

Can co-speech hand gestures facilitate learning of non-native tones?

Speech perception research has indicated that information from multiple input modalities (e.g., auditory, visual) facilitates second language (L2) speech learning. However, co-speech gestural information has shown mixed results. While L2 learners may benefit from this additional channel of information, it may also be inhibitory as learners may experience excessive cognitive load. This study examines the role of metaphoric hand gestures in L2 lexical tone learning using previously established laboratory training procedures. Training stimuli include Mandarin tones produced by native Mandarin speakers, with concurrent hand gestures mimicking pitch contours in space. Native Canadian English speakers are trained to perceive tones presented in one of three modalities: audio-visual (AV, speaker voice and face), audio-gesture (AG, speaker voice and hand gestures) and audio-visual-gesture (AVG). The effects of training are assessed by comparing the pre-training and post-training tone identification results. Greater improvements for the AVG compared to AV group would indicate the facilitative role of gestures. However, greater improvements for the AG or AV compared to AVG group would support the cognitive overload account. Findings are discussed in terms of how sensory-motor and cognitive domains cooperate functionally in speech perception and learning. [Equal contributions by KE, BH, and YW; work supported by SSHRC.]

Cross-language assimilation of lexical tone

We extend to lexical-tone systems a model of second-language perception, the Perceptual Assimilation Model (PAM) (Best & Tyler, 2007), to examine whether/how native-language lexical-tone inventory composition influences perception of novel tone. Native listeners of Cantonese, Thai, and Mandarin perform a tone mapping-rating assimilation task. Listeners hear CV syllables bearing all tones of Cantonese, Thai, Mandarin, and Yoruba - languages with different tone inventories. They (1) map the tone they hear to the nearest native tone category, and (2) provide a goodness rating on a 5-point scale (5 = perfect). As predicted by the PAM, listeners assimilated non-native tones to the phonetically-closest native tone categories. Listeners attended primarily to pitch-contour, and secondarily to pitch-height, contrasts for the mappings. E.g., Mandarin listeners assimilated the Thai high “level” (phonetically mid-to-high-rising) tone to Mandarin rising tone 76% of the time, and to Mandarin high-level tone only 22% of the time. Also as predicted, all novel tones did not assimilate equally well to native categories; mappings received ratings between 2.9-4.1, averaging 3.5. The groups’ different patterns of results indicate that novel-tone perception is influenced by experience with the native-language tone inventory, and that listeners attend to gradient phonetic detail to assimilate novel tones to native-tone categories. This work is supported by NSF grant 0965227 to J.A.

Categorizing Mandarin tones into listeners’ native prosodic categories: The role of phonetic properties

This study examined whether native speakers of non-tone languages (Australian English, and French) were able to perceive foreign Mandarin tones in a sentence environment according to their native prosodic categories. Results found that both English and French speakers were able to perceptually categorize foreign tones into their intonational categories (i-Categories), and that categorizations were based on the contextual phonetic similarities of the pitch contours they perceived between Mandarin tones and their native i-Categories. Results also showed that French speakers, but not English speakers, were able to detect the fine-detailed phonetic feature differences between Tone 3 and Tone 4 (low/falling tone vs. high-falling tone). The findings support a new extension of the Perceptual Assimilation Model (PAM; Best 1995) to suprasegmental phonology (So and Best 2008): that non-native prosodic categories (e.g. lexical tones) will be assimilated to the categories of listeners’ native prosodic system (e.g. intonation). In addition, rhythmic differences among languages may also contribute to perception of non-native tones.

Individual variability in cue-weighting and lexical tone learning

Speech sound patterns can be discerned using multiple acoustic cues. The relative weighting of these cues is known to be language-specific. Speech-sound training in adults induces changes in cue-weighting such that relevant acoustic cues are emphasized. In the current study, the extent to which individual variability in cue weighting contributes to differential success in learning to use foreign sound patterns was examined. Sixteen English-speaking adult participants underwent a sound-to-meaning training paradigm, during which they learned to incorporate Mandarin linguistic pitch contours into words. In addition to cognitive tests, measures of pitch pattern discrimination and identification were collected from all participants. Reaction time data from the discrimination task was subjected to 3-way multidimensional scaling to extract dimensions underlying tone perception. Two dimensions relating to pitch height and pitch direction were found to underlie non-native tone space. Good learners attended more to pitch direction relative to poor learners, before and after training. Training increased the ability to identify and label pitch direction. The results demonstrate that variability in the ability to successfully learn to use pitch in lexical contexts can be explained by pre-training differences in cue-weighting.

Cross-language perception of non-native tonal contrasts: effects of native phonological and phonetic influences.

This study examined the perception of the four Mandarin lexical tones by Mandarin-naïve Hong Kong Cantonese, Japanese, and Canadian English listener groups. Their performance on an identification task, following a brief familiarization task, was analyzed in terms of tonal sensitivities (A-prime scores on correct identifications) and tonal errors (confusions). The A-prime results revealed that the English listeners' sensitivity to Tone 4 identifications specifically was significantly lower than that of the other two groups. The analysis of tonal errors revealed that all listener groups showed perceptual confusion of tone pairs with similar phonetic features (T1-T2, T1-T4 and T2-T3 pairs), but not of those with completely dissimilar features (T1-T3, T2-T4, and T3-T4). Language-specific errors were also observed in their performance, which may be explained within the framework of the Perceptual Assimilation Model (PAM: Best, 1995; Best & Tyler, 2007). The findings imply that linguistic experience with native tones does not necessarily facilitate non-native tone perception. Rather, the phonemic status and the phonetic features (similarities or dissimilarities) between the tonal systems of the target language and the listeners' native languages play critical roles in the perception of non-native tones.

Identification of Acoustically Modified Mandarin Tones by Non-native Listeners

This study investigated identification of fragmented Mandarin tones by non-native listeners. Monosyllabic Mandarin words were digitally processed to generate intact, silent-center, center-only, and onset-only syllables. The syllables were recorded with two carrier phrases such that the offset of the carrier tone and the onset of the target tone were either continuous or discontinuous in fundamental frequency (F0). The syllables were presented with an original carrier phrase, excised from the carrier phrase, or excised and cross-spliced with another carrier phrase. Response accuracy and reaction time were measured, and tone confusion patterns were analyzed. Overall, tone identification varied as a function of modification and tone. Intact and center-only syllables were identified more accurately than silent-center and onset-only syllables. Tone 2 was consistently the most challenging tone to identify. Although the performance level of the third-year students approached that of native listeners reported in Lee, Tao, and Bond (2008), the non-native listeners did not show evidence of using coarticulatory information. Nonetheless, the continuity or discontinuity in F0 between the carrier and target tones did affect tone identification, suggesting the influence of context in non-native tone identification.

Perceptual similarities between native and non-native tones.

This study investigated the effects of L1 and L2 experience on the perceptual assimilation of non-native tones by native Mandarin or Thai listeners. Of these, 32 had 0.5–1.5 years of L2 learning experience while 40 had none. All listeners participated in a tonal assimilation task in which they first identified which tone in Mandarin or Thai sounded most similar to the Thai or Mandarin tone they heard, and then rated its goodness on a five point Likert scale. Stimuli included four Mandarin tones (high level, rising, falling-rising, and falling tones) and five Thai tones (mid, low-, falling, high-, and rising tones) on four monosyllables: /tuo/, /fej/, /kha/, /siau/, and a hum. The Thai listeners, regardless of L2 experience, assimilated more L1 tone categories to L2 than did the Mandarin listeners. Nonetheless, the experienced listeners from the two languages showed a high degree of consistency in terms of which tones were assimilated. The perceived similarities between native and non-native tones were not always predictable from their acoustic similarities, and varied with L1 and L2 experience. Results will be discussed in terms of some well-known perceptual assimilation models, such as PAM. [Work supported by GIS.]

Speaker variability and context in the identification of fragmented Mandarin tones by native and non-native listeners

This study investigated the individual and joint contribution of speaker variability, context, and type of acoustic input to the identification of Mandarin tones. Mandarin syllables produced by single vs. multiple speakers were digitally processed to generate intact, silent-center, center-only, and onset-only syllables to be presented in isolation or with a precursor carrier phrase. Forty native listeners and 55 non-native listeners were put under time pressure to identify the tones of the syllables. The results showed higher identification accuracy for single-speaker tones and tones presented in context. Tone identification accuracy also decreased as acoustic input was reduced. The speaker variability effect showed comparable magnitude for the native and non-native listeners. In contrast, non-native tone identification, compared to the native performance, was facilitated less by context and compromised more when acoustic input was minimal. Tone confusion analyses showed a Tone 2–Tone 3 confusion and a bias towards Tone 4 responses for both groups of listeners, but the patterns of confusion and bias are more variable in the non-native responses. The non-native listeners also showed inconsistent evidence of using F0 height for tone identification when acoustic input was minimal.

The developmental course of lexical tone perception in the first year of life

Perceptual reorganisation of infants’ speech perception has been found from 6 months for consonants and earlier for vowels. Recently, similar reorganisation has been found for lexical tone between 6 and 9 months of age. Given that there is a close relationship between vowels and tones, this study investigates whether the perceptual reorganisation for tone begins earlier than 6 months. Non-tone language English and French infants were tested with the Thai low vs. rising lexical tone contrast, using the stimulus alternating preference procedure. Four- and 6-month-old infants discriminated the lexical tones, and there was no decline in discrimination performance across these ages. However, 9-month-olds failed to discriminate the lexical tones. This particular pattern of decline in nonnative tone discrimination over age indicates that perceptual reorganisation for tone does not parallel the developmentally prior decline observed in vowel perception. The findings converge with previous developmental cross-language findings on tone perception in English-language infants [Mattock, K., & Burnham, D. (2006). Chinese and English infants’ tone perception: Evidence for perceptual reorganization. Infancy, 10(3)], and extend them by showing similar perceptual reorganisation for non-tone language infants learning rhythmically different non-tone languages (English and French).