Learning English vowels with different first-language vowel systems II: Auditory training for native Spanish and German speakers

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.

Learning English vowels: The effects of different phonetic training modes on Arabic learners' production and perceptiona)

This study investigated the effect of different types of phonetic training on potential changes in the production and perception of English vowels by Arabic learners of English. Forty-six Arabic learners of English were randomly assigned to one of three high variability vowel training programs: Perception training (High Variability Phonetic Training), Production training, and a Hybrid Training program (production and perception training). Pre- and post-tests (vowel identification, category discrimination, speech recognition in noise, and vowel production) showed that all training types led to improvements in perception and production. There was some evidence that improvements were linked to training type: learners in the Perception Training condition improved in vowel identification but not vowel production, while those in the Production Training condition showed only small improvements in performance on perceptual tasks, but greater improvement in production. However, the effects of training modality were complicated by proficiency, with high proficiency learners benefitting more from different types of training regardless of training mode than lower proficiency learners.

Acoustic and Articulatory Visual Feedback in Classroom L2 Vowel Remediation

This paper presents L2 vowel remediation in a classroom setting via two real-time visual feedback methods: articulatory ultrasound tongue imaging, which shows tongue shape and position, and a newly developed acoustic formant analyzer, which visualizes a point correlating with the combined effect of tongue position and lip rounding in a vowel quadrilateral. Ten Czech students of the Swedish language participated in the study. Swedish vowel production is difficult for Czech speakers since the languages differ significantly in their vowel systems. The students selected the vowel targets on their own and practiced in two classroom groups, with six students receiving two ultrasound training lessons, followed by one acoustic, and four students receiving two acoustic lessons, followed by one ultrasound. Audio data were collected pre-training, after the two sessions employing the first visual feedback method, and at post-training, allowing measuring Euclidean distance among selected groups of vowels and observing the direction of change within the vowel quadrilateral as a result of practice. Perception tests were performed before and after training, revealing that most learners perceived selected vowels correctly already before the practice. The study showed that both feedback methods can be successfully applied to L2 classroom learning, and both lead to the improvement in the pronunciation of the selected vowels, as well as the Swedish vowel set as a whole. However, ultrasound tongue imaging seems to have an advantage as it resulted in a greater number of improved targets.

Variability in cross-language and cross-dialect perception. How Irish and Chinese migrants process Australian English vowels

We investigate how three adult groups - experienced L2 English listeners; experienced D2 (second dialect) listeners; and native L1/D1 listeners - categorise Australian English (AusE) lax front vowels /ɪ e æ/ in /hVt/, /hVl/ and /mVl/ environments in a forced-choice categorisation task of synthesised continua. In study 1, AusE listeners show predictable categorisations, with an effect of coarticulation raising the vowel in perception for nasal onset stimuli, and a following lateral lowering the vowel in perception. In study 2, Irish (D2) and Chinese listeners (L2) have different categorisations than AusE listeners, likely guided by their D1/L1. Coarticulation influences the D1/D2 groups in similar ways, but results in more difficulty and less agreement for the Chinese. We also investigate the role of extralinguistic factors. For the Chinese listeners, higher proficiency in English does not correlate with more Australian-like categorisation behaviour. However, having fewer Chinese in their social network results in more Australian-like categorisation for some stimuli. These findings lend partial support to the role of experience and exposure in L2/D2 contexts, whereby categorisation is likely still driven by native categories, with increased exposure leading to better mapping, but not to a restructuring of underlying phonetic categories.

Discrimination of Second Language Vowel Contrasts and the Role of Phonological Short-Term Memory and Nonverbal Intelligence

Although extensive research has focused on the perceptual abilities of second language (L2) learners, a significant gap persists in understanding how cognitive functions like phonological short-term memory (PSTM) and nonverbal intelligence (IQ) impact L2 speech perception. This study sets out to investigate the discrimination of L2 English monophthongal vowel contrasts and to assess the effect of PSTM and nonverbal IQ on L2 speech perception. The participants consisted of adult monolingually-raised Greek speakers, who completed an AX discrimination test, a digit span test, and a nonverbal intelligence test. A control group of English speakers also completed the AX test. Data were analyzed using Bayesian regression models. The results revealed that Greek speakers exhibited below chance discrimination for the majority of L2 vowel contrasts, consistently underperforming in comparison to the control group. Intriguingly, the study did not provide substantial evidence in favor of more accurate discrimination of L2 contrasts by Greek participants with high PSTM compared to those with low PSTM. However, the study yielded compelling evidence indicating that Greek participants with higher IQ demonstrated superior accuracy in discriminating most L2 contrasts compared to their lower IQ counterparts. The limited influence of PSTM on speech perception suggests the need for further exploration, considering the potential impact of test methodologies and the intricate interplay of other confounding factors. Furthermore, the study uncovers a noteworthy relationship between nonverbal IQ and L2 speech perception, likely linked with the association of high IQ with enhanced attentional capacities, information processing abilities, and learning skills-all of which are pivotal for accurate speech perception.

Evaluating OpenAI's Whisper ASR: Performance analysis across diverse accents and speaker traits

This study investigates Whisper's automatic speech recognition (ASR) system performance across diverse native and non-native English accents. Results reveal superior recognition in American compared to British and Australian English accents with similar performance in Canadian English. Overall, native English accents demonstrate higher accuracy than non-native accents. Exploring connections between speaker traits [sex, native language (L1) typology, and second language (L2) proficiency] and word error rate uncovers notable associations. Furthermore, Whisper exhibits enhanced performance in read speech over conversational speech with modifications based on speaker gender. The implications of these findings are discussed.

The more the better? Effects of L1 tonal density and typology on the perception of non-native tones

This study investigates the effects of L1 tonal density and typology on naïve listeners' perception of L2 Cantonese tones and pitch-equivalent pure tones. Native speakers of two canonical tone languages (Vietnamese and Mandarin) and a pitch-accent language (Japanese) with varying degrees of tonal density were recruited as listeners in a discrimination task followed by a perceptual assimilation task. Results implied that Mandarin listeners with a sparser tone inventory exhibited significantly better performance than Vietnamese listeners, suggesting that denser tonality in L1 did not facilitate or even interfere with L2 tone perception. Furthermore, both groups of canonical tone listeners processed pitch contours in a domain-general manner, with comparable performance in the perception of lexical tones and pure tones. However, Japanese listeners of the pitch-accent language perceived pure tones better than lexical tones, showing a domain-specific mechanism. These findings suggest that both L1 tonal density and typology may modulate the perception of non-native tones.

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

OBJECTIVES

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.

DESIGN

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.

RESULTS

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.

CONCLUSIONS

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.

Memory-card vowel training for child and adult second-language learners: A first report

Japanese adults and Spanish-Catalan children received auditory phonetic training for English vowels using a novel paradigm, a version of the common children's card game Concentration. Individuals played a computer-based game in which they turned over pairs of cards to match spoken words, drawn from sets of vowel minimal pairs. The training was effective for adults, improving vowel recognition in a game that did not explicitly require identification. Children likewise improved over time on the memory card game, but not on the present generalisation task. This gamified training method can serve as a platform for examining development and perceptual learning.

Listen-and-repeat training in the learning of non-native consonant duration contrasts: influence of consonant type as reflected by MMN and behavioral methods

Phonological duration differences in quantity languages can be problematic for second language learners whose native language does not use duration contrastively. Recent studies have found improvement in the processing of non-native vowel duration contrasts with the use of listen-and-repeat training, and the current study explores the efficacy of similar methodology on consonant duration contrasts. 18 adult participants underwent two days of listen-and-repeat training with pseudoword stimuli containing either a sibilant or a stop consonant contrast. The results were examined with psychophysiological event-related potentials (mismatch negativity and P3), behavioral discrimination tests and a production task. The results revealed no training-related effects in the event-related potentials or the production task, but behavioral discrimination performance improved. Furthermore, differences emerged between the processing of the two consonant types. The findings suggest that stop consonants are processed more slowly than the sibilants, and the findings are discussed with regard to possible segmentation difficulties.

Training the pronunciation of L2 vowels under different conditions: the use of non-lexical materials and masking noise

The current study extends traditional perceptual high-variability phonetic training (HVPT) in a foreign language learning context by implementing a comprehensive training paradigm that combines perception (discrimination and identification) and production (immediate repetition) training tasks and by exploring two potentially enhancing training conditions: the use of non-lexical training stimuli and the presence of masking noise during production training. We assessed training effects on L1-Spanish/Catalan bilingual EFL learners' production of a difficult English vowel contrast (/æ/-/ʌ/). The participants (N = 62) were randomly assigned to either non-lexical (N = 24) or lexical (N = 24) training and were further subdivided into two groups, one trained in noise (N = 12) and one in silence (N = 12). An untrained control group (N = 14) was also tested. Training gains, measured through spectral distance scores (Euclidean distances) with respect to native speakers' productions of /æ/ and /ʌ/, were assessed through delayed word and sentence repetition tasks. The results showed an advantage of non-lexical training over lexical training, detrimental effects of noise for participants trained with nonwords, but not for those trained with words, and less accurate production of vowels elicited in isolated words than in words embedded in sentences, where training gains were only observable for participants trained with nonwords.

The Role of Talker Variability in Nonnative Phonetic Learning: A Systematic Review and Meta-Analysis

PURPOSE

High-variability phonetic training (HVPT) has been found to be effective on adult second language (L2) learning, but results are mixed in regards to the benefit of multiple talkers over single talker. This study provides a systematic review with meta-analysis to investigate the talker variability effect in nonnative phonetic learning and the factors moderating the effect.

METHOD

We collected studies with keyword search in major academic databases including EBSCO, ERIC, MEDLINE, ProQuest Dissertations & Theses, Elsevier, Scopus, Wiley Online Library, and Web of Science. We identified potential participant-, training-, and study-related moderators and conducted a random-effects model meta-analysis for each individual variable.

RESULTS

On the basis of 18 studies with a total of 549 participants, we obtained a small-level summary effect size (Hedges' g = 0.46, 95% confidence interval [CI; 0.08, 0.84]) for the immediate training outcomes, which was greatly reduced (g = -0.04, 95% CI [-0.46, 0.37]) after removal of outliers and correction for publication bias, whereas the effect size for immediate perceptual gains was nearly medium (g = 0.56, 95% CI [0.13, 1.00]) compared with the nonsignificant production gains. Critically, the summary effect sizes for generalizations to new talkers (g = 0.72, 95% CI [0.15, 1.29]) and for long-term retention (g = 1.09, 95% CI [0.39, 1.78]) were large. Moreover, the training program length and the talker presentation format were found to potentially moderate the immediate perceptual gains and generalization outcomes.

CONCLUSIONS

Our study presents the first meta-analysis on the role of talker variability in nonnative phonetic training, which demonstrates the heterogeneity and limitations of research on this topic. The results highlight the need for further investigation of the influential factors and underlying mechanisms for the presence or absence of talker variability effects. Supplemental Material https://doi.org/10.23641/asha.16959388.

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.

Training non-native vowel perception: In quiet or noise

Noise makes speech perception much more challenging for non-native listeners than for native listeners. Training for non-native speech perception is usually implemented in quiet. It remains unclear if background noise may benefit or hamper non-native speech perception learning. In this study, 51 Chinese-native listeners were randomly assigned into three groups, including vowel training in quiet (TIQ), vowel training in noise (TIN), and watching videos in English as an active control. Vowel identification was assessed before (T1), right after (T2), and three months after training (T3) in quiet and various noise conditions. Results indicated that compared with the video watching group, the TIN group improved vowel identification in both quiet and noise significantly more at T2 and at T3. In contrast, the TIQ group improved significantly more in quiet and also in non-speech noise conditions at T2, but the improvement did not hold at T3. Moreover, compared to the TIQ group, the TIN group showed significantly less informational masking at both T2 and T3 and less energetic masking at T3. These results suggest that L2 speech training in background noise may improve non-native vowel perception more effectively than TIQ background only. The implications for non-native speech perception learning are discussed.

The Role of Acoustic Similarity and Non-Native Categorisation in Predicting Non-Native Discrimination: Brazilian Portuguese Vowels by English vs. Spanish Listeners

This study tests whether Australian English (AusE) and European Spanish (ES) listeners differ in their categorisation and discrimination of Brazilian Portuguese (BP) vowels. In particular, we investigate two theoretically relevant measures of vowel category overlap (acoustic vs. perceptual categorisation) as predictors of non-native discrimination difficulty. We also investigate whether the individual listener’s own native vowel productions predict non-native vowel perception better than group averages. The results showed comparable performance for AusE and ES participants in their perception of the BP vowels. In particular, discrimination patterns were largely dependent on contrast-specific learning scenarios, which were similar across AusE and ES. We also found that acoustic similarity between individuals’ own native productions and the BP stimuli were largely consistent with the participants’ patterns of non-native categorisation. Furthermore, the results indicated that both acoustic and perceptual overlap successfully predict discrimination performance. However, accuracy in discrimination was better explained by perceptual similarity for ES listeners and by acoustic similarity for AusE listeners. Interestingly, we also found that for ES listeners, the group averages explained discrimination accuracy better than predictions based on individual production data, but that the AusE group showed no difference.

Non-native speech recognition sentences: A new materials set for non-native speech perception research

Research into non-native (L2) speech perception has increased the need for specialized experimental materials. The Non-Native Speech Recognition (NNSR) sentences are a new large-scale set of speech recognition materials for research with L2 speakers of English at CEFR level B1 (North, Ortega, & Sheehan, 2010) and above. The set comprises 439 triplets of sentences in three related conditions: semantically predictable, neutral, and anomalous. The sentences were created by combining a strongly or weakly contextually constrained sentence frame with a congruent or anomalous final keyword, and they were matched on a number of factors during development, to maintain consistency across conditions. This article describes the development process of the NNSR sentences, along with results of speech-in-noise intelligibility testing for L2 and native English speakers. Suggestions for the sentences’ application in a range of investigations and experimental designs are also discussed.

Mastery of Echoics in Chinese Establishes Bidirectional Naming in Chinese for Preschoolers with Naming in English

The onset of the verbal behavior developmental cusp of bidirectional naming (BiN) in a second language makes it possible for monolingual English-speaking children to learn names of things in a second language incidentally. We conducted 2 experiments to identify why monolingual English-speaking children cannot demonstrate BiN in another language when they demonstrated BiN in their native language. In Experiment I, using a group design (n = 32 preschoolers), we identified Chinese speech sounds that monolingual English-speaking children with BiN in English for familiar stimuli could not echo. In Experiment II, using a multiple-probe design, we investigated if mastery of echoics with the speech sounds identified in Experiment I would result in BiN in Chinese with 6 participants from Experiment I. The dependent variable was untaught responses to the probe stimuli presented following the naming experience based on the echoic stimuli from Experiment I. The results showed that echoic training was functionally related to the establishment of BiN in the second language. It appeared that the emission of accurate echoics might be the key to second-language BiN and that emergent correspondence between producing and hearing that occurs with the mastery of the echoic responding may be the source of reinforcement.

Perception of American-English Vowels by Early and Late Spanish-English Bilinguals

Increasing numbers of Hispanic immigrants are entering the US and learning American-English (AE) as a second language (L2). Previous studies investigating the relationship between AE and Spanish vowels have revealed an advantage for early L2 learners for their accuracy of L2 vowel perception. Replicating and extending such previous research, this study examined the patterns with which early and late Spanish-English bilingual adults assimilated naturally-produced AE vowels to their native vowel inventory and the accuracy with which they discriminated the vowels. Twelve early Spanish-English bilingual, 12 late Spanish-English bilingual, and 10 monolingual listeners performed perceptual-assimilation and categorical-discrimination tasks involving AE /i,ɪ,ɛ,ʌ,æ,ɑ,o/. Early bilinguals demonstrated similar assimilation patterns to late bilinguals. Late bilinguals' discrimination was less accurate than early bilinguals' and AE monolinguals'. Certain contrasts, such as /æ-ɑ/, /ʌ-ɑ/, and /ʌ-æ/, were particularly difficult to discriminate for both bilingual groups. Consistent with previous research, findings suggest that early L2 learning heightens Spanish-English bilinguals' ability to perceive cross-language phonetic differences. However, even early bilinguals' native-vowel system continues to influence their L2 perception.

Big data suggest strong constraints of linguistic similarity on adult language learning

When adults learn new languages, their speech often remains noticeably non-native even after years of exposure. These non-native variants ('accents') can have far-reaching socio-economic consequences for learners. Many factors have been found to contribute to a learners' proficiency in the new language. Here we examine a factor that is outside of the control of the learner, linguistic similarities between the learner's native language (L1) and the new language (Ln). We analyze the (open access) speaking proficiencies of about 50,000 Ln learners of Dutch with 62 diverse L1s. We find that a learner's L1 accounts for 9-22% of the variance in Ln speaking proficiency. This corresponds to 28-69% of the variance explained by a model with controls for other factors known to affect language learning, such as education, age of acquisition and length of exposure. We also find that almost 80% of the effect of L1 can be explained by combining measures of phonological, morphological, and lexical similarity between the L1 and the Ln. These results highlight the constraints that a learner's native language imposes on language learning, and inform theories of L1-to-Ln transfer during Ln learning and use. As predicted by some proposals, we also find that L1-Ln phonological similarity is better captured when subcategorical properties (phonological features) are considered in the calculation of phonological similarities.

Acoustic Sources of Accent in Second Language Japanese Speech

This study reports an exploratory analysis of the acoustic characteristics of second language (L2) speech which give rise to the perception of a foreign accent. Japanese speech samples were collected from American English and Mandarin Chinese speakers ( n = 16 in each group) studying Japanese. The L2 participants and native speakers ( n = 10) provided speech samples modeling after six short sentences. Segmental (vowels and stops) and prosodic features (rhythm, tone, and fluency) were examined. Native Japanese listeners ( n = 10) rated the samples with regard to degrees of foreign accent. The analyses predicting accent ratings based on the acoustic measurements indicated that one of the prosodic features in particular, tone (defined as high and low patterns of pitch accent and intonation in this study), plays an important role in robustly predicting accent rating in L2 Japanese across the two first language (L1) backgrounds. These results were consistent with the prediction based on phonological and phonetic comparisons between Japanese and English, as well as Japanese and Mandarin Chinese. The results also revealed L1-specific predictors of perceived accent in Japanese. The findings of this study contribute to the growing literature that examines sources of perceived foreign accent.

On the Role of Cognitive Abilities in Second Language Vowel Learning

This study investigated the role of different cognitive abilities-inhibitory control, attention control, phonological short-term memory (PSTM), and acoustic short-term memory (AM)-in second language (L2) vowel learning. The participants were 40 Azerbaijani learners of Standard Southern British English. Their perception of L2 vowels was tested through a perceptual discrimination task before and after five sessions of high-variability phonetic training. Inhibitory control was significantly correlated with gains from training in the discrimination of L2 vowel pairs. However, there were no significant correlations between attention control, AM, PSTM, and gains from training. These findings suggest the potential role of inhibitory control in L2 phonological learning. We suggest that inhibitory control facilitates the processing of L2 sounds by allowing learners to ignore the interfering information from L1 during training, leading to better L2 segmental learning.

Effects of Language Background on the Development of Sociolinguistic Awareness: The Perception of Accent Variation in Monolingual and Multilingual 5- to 7-Year-Old Children

As a result of complex international migration patterns, listeners in large urban centres such as London, UK, likely encounter large amounts of variation in spoken language. However, although dealing with variation is crucial to communication, relatively little is known about how the ability to do this develops. Still less is known about how this might be affected by language background. The current study investigates whether early experience with variation, specifically growing up bilingually in London, affects accent categorization. Sixty children (30 monolingual, 30 bilingual) aged 5-7 years, were tested in their ability to comprehend and categorize talkers in 2 out of 3 accents: a home, unfamiliar regional and unfamiliar foreign-accented variety. All children demonstrated high, above-chance performance in the comprehension task, but language background significantly affected the children's ability to categorize talkers. Bilinguals were able to categorize talkers in all accent conditions, but although all children were able to understand the talkers, monolingual children were only able to categorize talkers in the home-foreign accent condition. Overall, the results are consistent with an approach in which gradient representations of accent variation emerge alongside an understanding of how variation is used meaningfully within a child's environment.

The Role of Temporal Acoustic Exaggeration in High Variability Phonetic Training: A Behavioral and ERP Study

High variability phonetic training (HVPT) has been found to be effective in helping adult learners acquire non-native phonetic contrasts. The present study investigated the role of temporal acoustic exaggeration by comparing the canonical HVPT paradigm without involving acoustic exaggeration with a modified adaptive HVPT paradigm that integrated key temporal exaggerations in infant-directed speech (IDS). Sixty native Chinese adults participated in the training of the English /i/ and /i/ vowel contrast and were randomly assigned to three subject groups. Twenty were trained with the typical HVPT paradigm (the HVPT group), twenty were trained under the modified adaptive approach with acoustic exaggeration (the HVPT-E group), and twenty were in the control group. Behavioral tasks for the pre- and post- tests used natural word identification, synthetic stimuli identification, and synthetic stimuli discrimination. Mismatch negativity (MMN) responses from the HVPT-E group were also obtained to assess the training effects in within- and across- category discrimination without requiring focused attention. Like previous studies, significant generalization effects to new talkers were found in both the HVPT group and the HVPT-E group. The HVPT-E group, by contrast, showed greater improvement as reflected in larger progress in natural word identification performance. Furthermore, the HVPT-E group exhibited more native-like categorical perception based on spectral cues after training, together with corresponding training-induced changes in the MMN responses to within- and across- category differences. These data provide the initial evidence supporting the important role of temporal acoustic exaggeration with adaptive training in facilitating phonetic learning and promoting brain plasticity at the perceptual and pre-attentive neural levels.

Interactions between speech perception and production during learning of novel phonemic categories

A successful language learner must be able to perceive and produce novel sounds in their second language. However, the relationship between learning in perception and production is unclear. Some studies show correlations between the two modalities; however, other studies have not shown such correlations. In the present study, I examine learning in perception and production after training in a distributional learning paradigm. Training modality is manipulated, while testing modality remained constant. Overall, participants showed substantial learning in the modality in which they were trained; however, learning across modalities shows a more complex pattern. Although individuals trained in perception improved in production, individuals trained in production did not show substantial learning in perception. That is, production during training disrupted perceptual learning. Further, correlations between learning in the two modalities were not strong. Several possible explanations for the pattern of results are explored, including a close examination of the role of production variability, and the results are explained using a paradigm appealing to shared cognitive resources. The article concludes with a discussion of the implications of these results for theories of second-language learning, speech perception, and production.

Effects of Exposure and Vowel Space Distribution on Phonetic Drift: Evidence from American English Learners of French

Recent work by Chang has shown that even at the very earliest stages of second language (L2) acquisition, the phonetic implementation of speakers' native English phoneme categories is slightly modified by contact with L2 Korean, which is referred to as "phonetic drift." This study investigates whether rapid phonetic drift generalizes to another pairing of languages. We examined naïve American English learners of French, who were recorded producing both American English and French vowels after one and six weeks of a study abroad program in Paris. In addition, the Study Abroad group is compared with proficient American English L1 speakers of French who have been residents of Paris for at least five years, to investigate the impact of long-term use of an L2 on the vowel categories of L1. Whereas the Study Abroad group showed no evidence of phonetic drift after six weeks, the Paris Residents' American English vowel space shifted along F1 and several English vowels demonstrated clear movement toward French monolingual norms. A closer look at the high vowels provides insight into how phonetic categories are influenced both by drift and by a pressure to keep vowel categories distinct between the languages. The results are also discussed with respect to potential effects of the size of the vowel inventory and the amount of input required to cause phonetic drift.

Computer-based auditory training improves second-language vowel production in spontaneous speech

The current study examined the effectiveness of computer-based auditory training on Greek speakers' production of English vowels in read sentences and in spontaneous speech. Another group of Greek speakers served as controls. Improvement was evaluated pre- and post-training via an identification task performed by English listeners and by an acoustic analysis of vowel quality using a combined F1/F2 measure. Auditory training improved English vowel production in read sentences and in spontaneous speech for the trained group, with improvement being larger in read sentences. The results indicate that auditory training can have ecological validity since it enhances learners' production beyond the (read) sentence level.

Perceptual Training of Second-Language Vowels: Does Musical Ability Play a Role?

The present study attempts to extend the research on the effects of phonetic training on the production and perception of second-language (L2) vowels. We also examined whether success in learning L2 vowels through high-variability intensive phonetic training is related to the learners' general musical abilities. Forty Azerbaijani learners of Standard Southern British English participated in a pre-test/training/post-test setting. Discrimination and production tests were used in pre- and post-tests. The participants' musical ability was evaluated through three musical aptitude tests. Results revealed a significant improvement in the discrimination and production of L2 vowels after training. However, the lack of a one-to-one relationship between production and perception gains suggests distinct representations underlying L2 speech perception and production. There was no significant correlation between overall musical ability scores and L2 vowel learning, however, results revealed a correlation between discrimination improvements and tonal memory. This suggests tonal memory facilitates the perceptual learning of the novel phonological structure of L2.

What Can Lexical Tone Training Studies in Adults Tell Us about Tone Processing in Children?

A growing number of studies on the acquisition of lexical tone by adult learners have revealed that factors such as language background, musical experience, cognitive abilities, and neuroanatomy all play a role in determining tone learning success. On the basis of these findings, it has been argued that the effectiveness of tone learning in adulthood depends on individual differences in these factors. However, it is not clear whether similar individual differences play an analogous role in tone learning in childhood. Indeed, relatively few studies have made comparisons between how adults and children learn lexical tones. Here, we review recent developments for tone learning in both adults and children. The review covers tone training in a range of contexts, including in naive listeners, in native speakers of other tone languages, in listeners with varying levels of musical experience, and in individuals with speech and hearing disorders. Finally, we discuss the parallels between adult and child tone learning, and provide recommendations concerning how findings in adult tone training can provide insights into tone learning for children by accommodating the needs of individual learners.

Acoustic Properties Predict Perception of Unfamiliar Dutch Vowels by Adult Australian English and Peruvian Spanish Listeners

Research suggests that the size of the second language (L2) vowel inventory relative to the native (L1) inventory may affect the discrimination and acquisition of L2 vowels. Models of non-native and L2 vowel perception stipulate that naïve listeners' non-native and L2 perceptual patterns may be predicted by the relationship in vowel inventory size between the L1 and the L2. Specifically, having a smaller L1 vowel inventory than the L2 impedes L2 vowel perception, while having a larger one often facilitates it. However, the Second Language Linguistic Perception (L2LP) model specifies that it is the L1–L2 acoustic relationships that predict non-native and L2 vowel perception, regardless of L1 vowel inventory. To test the effects of vowel inventory size vs. acoustic properties on non-native vowel perception, we compared XAB discrimination and categorization of five Dutch vowel contrasts between monolinguals whose L1 contains more (Australian English) or fewer (Peruvian Spanish) vowels than Dutch. No effect of language background was found, suggesting that L1 inventory size alone did not account for performance. Instead, participants in both language groups were more accurate in discriminating contrasts that were predicted to be perceptually easy based on L1–L2 acoustic relationships, and were less accurate for contrasts likewise predicted to be difficult. Further, cross-language discriminant analyses predicted listeners' categorization patterns which in turn predicted listeners' discrimination difficulty. Our results show that listeners with larger vowel inventories appear to activate multiple native categories as reflected in lower accuracy scores for some Dutch vowels, while listeners with a smaller vowel inventory seem to have higher accuracy scores for those same vowels. In line with the L2LP model, these findings demonstrate that L1–L2 acoustic relationships better predict non-native and L2 perceptual performance and that inventory size alone is not a good predictor for cross-language perceptual difficulties.

Comparison of perception-production vowel spaces for speakers of Standard Modern Greek and two regional dialects

This study compared the perception-production vowel spaces for speakers of Standard Modern Greek and two regional dialects. In experiment 1, participants produced the Greek vowels and chose vowel best exemplars (prototypes) in a natural sentence spoken in the participants' dialect. In experiment 2, the speakers who had made the recordings for experiment 1 chose themselves vowel prototypes. Cross-dialectal differences were found in both perception and production. Across dialects and experiments, participants' perceptual space was exaggerated compared to the acoustic one. Because participants' perceptual space in experiment 2 was calibrated to the participants own voice, perception and production data are directly comparable.

Phonetic Encoding of Coda Voicing Contrast under Different Focus Conditions in L1 vs. L2 English

This study investigated how coda voicing contrast in English would be phonetically encoded in the temporal vs. spectral dimension of the preceding vowel (in vowel duration vs. F1/F2) by Korean L2 speakers of English, and how their L2 phonetic encoding pattern would be compared to that of native English speakers. Crucially, these questions were explored by taking into account the phonetics-prosody interface, testing effects of prominence by comparing target segments in three focus conditions (phonological focus, lexical focus, and no focus). Results showed that Korean speakers utilized the temporal dimension (vowel duration) to encode coda voicing contrast, but failed to use the spectral dimension (F1/F2), reflecting their native language experience—i.e., with a more sparsely populated vowel space in Korean, they are less sensitive to small changes in the spectral dimension, and hence fine-grained spectral cues in English are not readily accessible. Results also showed that along the temporal dimension, both the L1 and L2 speakers hyperarticulated coda voicing contrast under prominence (when phonologically or lexically focused), but hypoarticulated it in the non-prominent condition. This indicates that low-level phonetic realization and high-order information structure interact in a communicatively efficient way, regardless of the speakers’ native language background. The Korean speakers, however, used the temporal phonetic space differently from the way the native speakers did, especially showing less reduction in the no focus condition. This was also attributable to their native language experience—i.e., the Korean speakers’ use of temporal dimension is constrained in a way that is not detrimental to the preservation of coda voicing contrast, given that they failed to add additional cues along the spectral dimension. The results imply that the L2 phonetic system can be more fully illuminated through an investigation of the phonetics-prosody interface in connection with the L2 speakers’ native language experience.

Gradient of learnability in teaching English pronunciation to Korean learners

This paper aims to propose a gradient of learnability as a criterion for setting priorities in pronunciation teaching. A total of 40 Korean subjects (mostly aged 12 year) were tested on their discrimination ability of English sounds before and after participating in a high variability phonetic training (HVPT) program for 4 weeks. This study shows highly promising results for pronunciation teaching with the HVPT method. First, lower level learners show greater improvements in phoneme discrimination ability compared to upper level learners. Second, consonants are better discriminated than vowels and greater improvements are seen with consonant contrasts than with vowels that have a lower functional load. Third, many of the sounds with high functional load have a high learnability. Fourth, greater improvements are seen with sounds that are poorly identified before the training than sounds that are well-identified. Fifth, young learners also benefit from the HVPT, much like highly motivated adult learners. A learnability gradient was established on the basis of the phoneme learnability index and the pairwise learnability index. On the basis of the constructed gradient of learnability and the concept of functional load, a set of priorities was provided for teaching English pronunciation to young Korean learners.

Spanish is better than English for discriminating Portuguese vowels: acoustic similarity versus vowel inventory size

Second language (L2) learners often struggle to distinguish sound contrasts that are not present in their native language (L1). Models of non-native and L2 sound perception claim that perceptual similarity between L1 and L2 sound contrasts correctly predicts discrimination by naïve listeners and L2 learners. The present study tested the explanatory power of vowel inventory size versus acoustic properties as predictors of discrimination accuracy when naïve Australian English (AusE) and Iberian Spanish (IS) listeners are presented with six Brazilian Portuguese (BP) vowel contrasts. Our results show that IS listeners outperformed AusE listeners, confirming that cross-linguistic acoustic properties, rather than cross-linguistic vowel inventory sizes, successfully predict non-native discrimination difficulty. Furthermore, acoustic distance between BP vowels and closest L1 vowels successfully predicted differential levels of difficulty among the six BP contrasts, with BP /e-i/ and /o-u/ being the most difficult for both listener groups. We discuss the importance of our findings for the adequacy of models of L2 speech perception.

Effects of speech practice on fast mapping in monolingual and bilingual speakers

PURPOSE

This study examines the effects of the levels of speech practice on fast mapping in monolingual and bilingual speakers.

METHOD

Participants were 30 English-speaking monolingual and 30 Spanish-English bilingual young adults. Each participant was randomly assigned to 1 of 3 practice conditions prior to the fast-mapping task: (a) intensive speech practice, (b) moderate speech practice, or (c) no practice. In a fast-mapping experiment, each participant was briefly exposed to novel objects and their corresponding novel words. Participants' knowledge of the target novel words was assessed immediately after the exposures.

RESULTS

There were significant effects of speech practice on fast mapping for both monolingual and bilingual adults. It is important to note that participants' language experience also played a role in their fast-mapping performance.

CONCLUSION

The findings suggest that speech practice, interacting with language experience, facilitates the processes for fast mapping.

Predicting Native English-Like Performance by Native Japanese Speakers

This study tested the predictions of the Speech Learning Model (SLM, Flege, 1988) on the case of native Japanese (NJ) speakers' perception and production of English /ɹ / and /l/. NJ speakers' degree of foreign accent, intelligibility of /ɹ -l/ productions, and ability to perceive natural speech /ɹ -l/ were assessed as a function of length of residency in North America, age of arrival in North America, years of student status in an English environment, and percentage of Japanese usage. Additionally, the extent to which NJ speakers' utilized the F3 onset cue when differentiating /ɹ -l/ in perception and production was assessed, this cue having previously been shown to be the most reliable indicator of category membership. As predicted, longer residencies predicted more native English-like accents, more intelligible productions, and more accurate natural speech identifications; however, no changes were observed in F3 reliance, indicating that though performance improves it does so through reliance on other cues.

The effect of native vowel processing ability and frequency discrimination acuity on the phonetic training of English vowels for native speakers of Greek

The perception and production of nonnative phones in second language (L2) learners can be improved via auditory training, but L2 learning is often characterized by large differences in performance across individuals. This study examined whether success in learning L2 vowels, via five sessions of high-variability phonetic training, related to the learners' native (L1) vowel processing ability or their frequency discrimination acuity. A group of native speakers of Greek received training, while another completed the pre-/post-tests but without training. Pre-/post-tests assessed different aspects of their L2 and L1 vowel processing and frequency acuity. L2 and L1 vowel processing were assessed via: (a) Natural English (L2) vowel identification in quiet and in multi-talker babble, and natural Greek (L1) vowel identification in babble; (b) the categorization of synthetic English and Greek vowel continua; and (c) discrimination of the same continua. Frequency discrimination acuity was assessed for a nonspeech continuum. Frequency discrimination acuity was related to measures of both L1 and L2 vowel processing, a finding that favors an auditory processing over a speech-specific explanation for individual variability in L2 vowel learning. The most efficient frequency discriminators at pre-test were also the most accurate both in English vowel perception and production after training.