Non-native Phoneme Research Articles

Plasticity in older infants' perception of phonetic contrasts: The role of selective attention in context.

Developmental plasticity refers to conditions and circumstances that increase phenotypic variability. In infancy, plasticity expands and contracts depending on domains of functioning, developmental history, and timing. In terms of language processing, infants attend to and discriminate both native and non-native phonetic contrasts, but selectively attune to their native phonemes by the end of the first postnatal year. However, relevant studies have excluded factors regarded as promoters of attention such as infant-directed (ID) speech, synchronous multimodal presentations, and female speakers. Here we investigated whether English-learning 11-month-olds would discriminate a non-native phonetic contrast while manipulating these factors. Results showed significant discrimination of the non-native contrast, regardless of speech register, provided that they were presented by a dynamic female speaker. Interestingly, when a static object or a dynamic male ID speaker replaced the female, no significant discrimination was found. These results show infants to be capable of discriminating non-native phonetic contrasts in an enhanced context at an age when they have been characterized as not being able to do so. Synchronized, multimodal information from female speakers allowed infants to perceive difficult non-native phonemes, highlighting the importance of an ecologically valid context for studying speech perception and language learning in early development.

The developmental pattern of native and non-native speech perception during the 1st year of life in Japanese infants

Language development during the 1st year of life is characterized by perceptual attunement: following language-general perception, a decline in the perception of non-native phonemes and a parallel increase in or maintenance of the perception of native phonemes. While this general pattern is well established, there are still many gaps in the literature. First, most evidence documenting these patterns comes from “Minority world countries” with only a limited number of studies from “Majority world countries”, limiting the range of languages and contrasts assessed. Second, few studies test both the developmental patterns of native and non-native speech perception in the same group of infants, making it hard to draw conclusions on simultaneous decline in non-native and increase in native speech perception. Such limitations are in part due to the effort that goes into testing developing speech sound perception, where usually only discrimination of one contrast per infant can be tested at a time. The present study thus set out to assess the feasibility of assessing a given infant on their discrimination of two speech sound contrasts during the same lab visit. It leveraged the presence of documented patterns of the improvement of native and the decline of non-native phoneme discrimination abilities in Japanese, therefore assessing native and non-native speech perception in Japanese infants from 6 to 12 months of age. Results demonstrated that 76 % of infants contributed discrimination data for both contrasts. We found a decline in non-native speech perception evident in discrimination of the non-native /ɹ/-/l/ consonant contrast at 9–11, but not at 11–13 months of age. Additionally, a parallel increase in native speech perception was demonstrated evident in an absence of native phonemic vowel length discrimination at 6–7 and 9–11 months and a discrimination of this contrast at 11–13 months of age. These results, based on a simultaneous assessment of native and non-native speech perception in Japanese-learning infants, demonstrate the feasibility of assessing the discrimination of two contrasts in one testing session and corroborate theoretical proposals on two hallmarks of perceptual attunement: a decrease in non-native and a facilitation in native speech perception during the first year of life.

Exploring individual differences in native phonetic perception and their link to nonnative phonetic perception.

Adults differ considerably in their perception of both native and nonnative phonemes. For instance, when presented with continua of native phonemes on two-alternative forced choice (2AFC) or visual analog scaling (VAS) tasks, some people show sudden changes in responses (i.e., steep identification slopes) and others show gradual changes (i.e., shallow identification slopes). Moreover, some adults are more successful than others at learning unfamiliar phonemes. The predictors of these individual differences and the relationships between them are poorly understood. It also remains unclear to what extent different tasks (2AFC vs. VAS) may reflect distinct individual differences in perception. In two experiments, we addressed these questions by examining the relationships between individual differences in performance on native and nonnative phonetic perception tasks. We found that shallow 2AFC identification slopes were not related to shallow VAS identification slopes but were related to inconsistent VAS responses. Additionally, our results suggest that consistent native perception may play a role in promoting successful nonnative perception. These findings help characterize the nature of individual differences in phonetic perception and contribute to our understanding of how to measure such differences. This work also has implications for encouraging successful acquisition of new languages in adulthood. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The direction of attention in second language phonological contrast learning.

This study attempted to describe why some individuals are more successful when learning to perceive the sounds of a second language by analyzing the role attention plays in perceptual learning. Fifty-seven monolingual English-speaking adults completed the study. The participants underwent a perceptual learning paradigm presenting the novel contrast, the voicing contrast between Thai /b/ and /p/. The experiment consisted of a 40-item pretest, 480-trial learning phase, and 40-item posttest. Approximately half of the participants (n = 30) were given explicit instruction to listen for the specific contrast prior to the learning phase; other participants were not told the nature of the contrast. The Attention Network Test (ANT) from Fan, McCandliss, Sommer, Raz, and Posner [(2002). J. Cogn. Neurosci. 14(3), 340-347] was used to assess attentional networks. Generalized linear models and linear mixed effect models (LME) were fit to predict the participants' post-test scores based on ANT subscores, experimental group, and learning block (LME only). The results showed a correlation between attentional control and the ability to learn non-native phoneme contrasts regardless of instruction. In addition, there was a positive interaction between attentional control and the provision of explicit instructions during the learning process, such that individuals with high attentional control learned better when they received explicit instruction prior to training.

Difficulties in decoupling articulatory gestures in L2 phonemic sequences: the case of Mandarin listeners’ perceptual deletion of English post-vocalic laterals

Nonnative or second language (L2) perception of segmental sequences is often characterised by perceptual modification processes, which may "repair" a nonnative sequence that is phonotactically illegal in the listeners' native language (L1) by transforming the sequence into a sequence that is phonotactically legal inthe L1. Often repairs involve the insertion of phonetic materials (epenthesis), but we focus, here, on the less-studied phenomenon of perceptual deletion of nonnative phonemes by testing L1 Mandarin listeners' perception of post-vocalic laterals in L2 English using the triangulating methods of a cross-language goodness rating task, an AXB task, and an AX task. The data were analysed in the framework of the Perceptual Assimilation Model (PAM/PAM-L2), and we further investigated the role of L2 vocabulary size on task performance. The experiments indicate that perceptual deletion occurs when the post-vocalic lateral overlaps with the nucleus vowel in terms of tongue backness specification. In addition, Mandarin listeners' discrimination performance in some contexts was significantly correlated with their English vocabulary size, indicating that continuous growth of vocabulary knowledge can drive perceptual learning of novel L2 segmental sequences and phonotactic structures.

Effects of socio-economic status on infant native and non-native phoneme discrimination.

Infants undergo fundamental shifts in perception that are reported to be critical for language acquisition. In particular, infants' perception of native and non-native sounds begins to align with the properties of their native sound system. Thus far, empirical evidence for this transition - perceptual narrowing - has drawn from socio-economically and linguistically narrow populations from limited world regions. In this study, infants were sampled across diverse socio-economic strata and linguistic development in Singapore. One hundred and 16 infants were tested on their ability to discriminate both a native phonetic contrast (/ba/ versus /da/) and a non-native Hindi contrast (/ta/ versus /ʈa). Infants ranged in age from 6 to 12 months. Associations between age and discrimination varied by contrast type. Results demonstrated that infants' native sensitivities were positively predicted by family SES, whereas non-native sensitivities were not. Maternal socio-economic factors uniquely predicted native language sensitivity. Findings suggest that infants' sensitivity to native sound contrasts is influenced by their family socio-economic status. RESEARCH HIGHLIGHTS: We investigated effects of socio-economic status on infant speech perception. Infants were tested on native and non-native speech discrimination. Socio-economic status predicted native speech discrimination. Maternal occupation was a key predictor of native speech discrimination.

The P300 event related potential predicts phonological working memory skills in school-aged children.

The P300 event related potential (ERP) has been cited as a marker of phonological working memory (PWM); however, little is known regarding its relationship to behavioral PWM skills in early school-aged children. The current study investigates the P300 ERP recorded in response to native and non-native (English and Spanish) phoneme contrasts as a predictor of PWM skills in monolingual English-speaking first and second grade children. Thirty-three typically developing children, ages 6–9, completed a battery of phonological processing, language, and cognitive assessments. ERPs were recorded within an auditory oddball paradigm in response to both English phoneme contrasts (/ta/, /pa/) and Spanish contrasts (/t̪a/, /d̪a/). The P300 ERP recorded in response to English phoneme contrasts significantly predicted standard scores on the Nonword Repetition subtest of the Comprehensive Test of Phonological Processing, Second Edition. Spanish contrasts did not elicit a P300 response, nor were amplitude or latency values within the P300 timeframe (250–500 ms) recorded in response to Spanish contrasts related to English nonword repetition performance. This study provides further evidence that the P300 ERP in response to native phonemic contrasts indexes PWM skills, specifically nonword repetition performance, in monolingual children. Further work is necessary to determine the extent to which the P300 response to changing phonological stimuli reflects PWM skills in other populations.

How do non-native phonemes impact learning words in a second language? Evidence from eyetracking and EEG in a laboratory word learning study

A classic finding holds that listeners have significant difficulty categorizing and discriminating unfamiliar/nonnative phonemes. In the present study we examined how this influences learning new words in a second language (L2). Adult monolingual English speakers were trained on a pseudo-French vocabulary, by matching images of cartoon “aliens” to auditory CVCV words incorporating French vowels and consonants. Of interest was comparing words incorporating vowels similar to English to those containing highly unfamiliar vowels (here, the French high front rounded vowel [y]). Accuracy, eyetracking and event-related potentials (ERPs, measured with EEG) were then used to assess word recognition post-training. The neurocognitive measures indicated weakened recognition of words containing the novel [y] vowel, compared to words with vowels that more closely resembled those in English. Furthermore, we found that a training regime that emphasized discriminating easily confused vowels (i.e., [u] vs. [y]) during learning yielded somewhat improved recognition, both immediately after training and in a follow-up session. Interestingly, learning words containing the unfamiliar [y] vowel was not accompanied by improved AX discrimination of this vowel. The results have key implications for how we understand the role of phonology in L2 word representations, and for how we approach L2 teaching.

Modified Input Training and Cue Reweighting in Second Language Vowel Perception

Many studies have shown that the High Variability Phonetic Training method can help L2 learners acquire nonnative phoneme contrasts. However, few studies have explored how this paradigm can work using modified input. We investigate L1 Mandarin learners of English as a foreign language and their perception of the tense/lax [i]/[ɪ] contrast. Mandarin learners rely on durational (rather than spectral) cues to distinguish these L2 vowels. In an ABX discrimination task, the experimental group was trained using both natural and synthesized stimuli whose vowels had been systematically lengthened or shortened thus removing the reliability of the durational cue. The control group was trained using natural stimuli only. The pre- and post-tests were identification tasks. An ANCOVA comparing the pre- and post-test identification accuracy revealed that the experimental group improved significantly more than the control group. The modified durational input allows participants to re-weight their processing cues and attend to spectral differences.

Early Development of Neural Speech Encoding Depends on Age but Not Native Language Status: Evidence From Lexical Tone.

We investigated the development of early-latency and long-latency brain responses to native and non-native speech to shed light on the neurophysiological underpinnings of perceptual narrowing and early language development. Specifically, we postulated a two-level process to explain the decrease in sensitivity to non-native phonemes toward the end of infancy. Neurons at the earlier stages of the ascending auditory pathway mature rapidly during infancy facilitating the encoding of both native and non-native sounds. This growth enables neurons at the later stages of the auditory pathway to assign phonological status to speech according to the infant's native language environment. To test this hypothesis, we collected early-latency and long-latency neural responses to native and non-native lexical tones from 85 Cantonese-learning children aged between 23 days and 24 months, 16 days. As expected, a broad range of presumably subcortical early-latency neural encoding measures grew rapidly and substantially during the first two years for both native and non-native tones. By contrast, long-latency cortical electrophysiological changes occurred on a much slower scale and showed sensitivity to nativeness at around six months. Our study provided a comprehensive understanding of early language development by revealing the complementary roles of earlier and later stages of speech processing in the developing brain.

Hand Gestures Facilitate the Acquisition of Novel Phonemic Contrasts When They Appropriately Mimic Target Phonetic Features.

Purpose Research has shown that observing hand gestures mimicking pitch movements or rhythmic patterns can improve the learning of second language (L2) suprasegmental features. However, less is known about the effects of hand gestures on the learning of novel phonemic contrasts. This study examines (a) whether hand gestures mimicking phonetic features can boost L2 segment learning by naive learners and (b) whether a mismatch between the hand gesture form and the target phonetic feature influences the learning effect. Method Fifty Catalan native speakers undertook a short multimodal training session on two types of Mandarin Chinese consonants (plosives and affricates) in either of two conditions: Gesture and No Gesture. In the Gesture condition, a fist-to-open-hand gesture was used to mimic air burst, while the No Gesture condition included no such use of gestures. Crucially, while the hand gesture appropriately mimicked the air burst produced in plosives, this was not the case for affricates. Before and after training, participants were tested on two tasks, namely, the identification task and the imitation task. Participants' speech output was rated by five Chinese native speakers. Results The perception results showed that training with or without gestures yielded similar degrees of improvement for the identification of aspiration contrasts. By contrast, the production results showed that, while training without gestures did not help improve L2 pronunciation, training with gestures improved pronunciation, but only when the given gestures appropriately mimicked the phonetic properties they represented. Conclusions Results revealed that the efficacy of observing hand gestures on the learning of nonnative phonemes depends on the appropriateness of the form of those gestures relative to the target phonetic features. That is, hand gestures seem to be more useful when they appropriately mimic phonetic features. Supplemental Material https://doi.org/10.23641/asha.13105442.

Perceptual discrimination measure of non-native phoneme perception in early and late Spanish-English and Japanese-English bilinguals

This study examined speech discrimination of English vowels /ɑ/ (as in “hot”), /ʌ/ (as in “hut”), and /æ/ (as in “hat”) by non-native English speakers, using an AXB discrimination task. Previous research shows that a person’s first language (L1) changes how speech is perceived in a second learned language (L2). Spanish and Japanese were chosen for this study because both languages share the same five spectrally different vowels, but Japanese additionally distinguishes between short and long versions of those five vowels. L2 proficiency and/or amount of L2 input were used as additional predictor variables. The target populations were early and late Spanish-English bilinguals and early and late Japanese-English bilinguals, which were compared to a control group of monolingual American English speakers. We are currently collecting data and based on previous studies (Shafer et al., under review), we predict: (1) monolinguals and early-bilinguals will show better performance than late-bilinguals; (2) discrimination of /ʌ/ vs. /æ/ contrast will be easier than other contrasts, /ʌ/ vs. /ɑ/ and /ɑ/ vs. /æ/. Our findings will address how L1 spectral-temporal cues and L2 age of acquisition affect L2 speech perception.

Articulatory and perceptual cues to non-native phoneme perception: Cross-modal training for early learners

Non-native phoneme perception can be challenging for adult learners. This article explores two routes to strengthening early representations of non-native targets: perceptual training, which focuses on auditory discrimination of novel contrasts, and articulatory training, which highlights the articulatory gestures of non-native categories. Of particular interest is whether cross-modal transfer from production to perception is beneficial to improving discrimination. A longitudinal experiment integrating both training types found that articulatory training did not improve discrimination once perceptual learning had taken place. However, a follow-up experiment found an equivalent benefit for perceptual and articulatory training when each was presented as the only learning style to separate groups of learners. These findings suggest that articulatory learning can ‘cross over’ to assist acquisition in the perceptual domain, and may play a key role for second language (L2) learners struggling with both perception and production of novel phoneme categories.

Reduced perceptual narrowing in synesthesia

Synesthesia is a neurologic trait in which specific inducers, such as sounds, automatically elicit additional idiosyncratic percepts, such as color (thus "colored hearing"). One explanation for this trait-and the one tested here-is that synesthesia results from unusually weak pruning of cortical synaptic hyperconnectivity during early perceptual development. We tested the prediction from this hypothesis that synesthetes would be superior at making discriminations from nonnative categories that are normally weakened by experience-dependent pruning during a critical period early in development-namely, discrimination among nonnative phonemes (Hindi retroflex /d̪a/ and dental /ɖa/), among chimpanzee faces, and among inverted human faces. Like the superiority of 6-mo-old infants over older infants, the synesthetic groups were significantly better than control groups at making all the nonnative discriminations across five samples and three testing sites. The consistent superiority of the synesthetic groups in making discriminations that are normally eliminated during infancy suggests that residual cortical connectivity in synesthesia supports changes in perception that extend beyond the specific synesthetic percepts, consistent with the incomplete pruning hypothesis.

중국어를 학습하는 한국어 모국어 화자의 중국어 성조 지각과 산출

Non-tonal language speakers may have difficulty learning second language lexical tones. In the present study, we explored this issue with Korean-speaking learners of Mandarin Chinese (i.e., non-tonal first language speakers) by examining their perception and production of Mandarin lexical tones. In the perception experiment, the Korean learners were asked to listen to the tone of each stimulus and assign it to one of four Mandarin lexical tones using the response keys; in the production experiment, the learners provided speech production data for the lexical tones and then their productions were identified by native listeners of Mandarin Chinese. Our results showed that the Korean learners of Mandarin Chinese had difficulty in perceptually distinguishing Tone 2 and Tone 3, with the most frequent production error being the mispronunciation of Tone 3 as Tone 2. We also investigated whether unfamiliar non-native phonemes (i.e., Chinese phonemes) that do not exist in the native language phonemic inventory (i.e., Korean) may hinder the processing of the non-native lexical tones. We found no evidence for such effects, neither for the perception nor for the production of the tones.

Training Non-Native Consonant Production with Perceptual and Articulatory Cues

Background/Aims: Adult learners often struggle to produce novel phonemes in a second language and lack clear articulatory targets. This study investigates the combined efficacy of perceptual and articulatory training, the latter involving explicit instruction about tongue position and laryngeal control, for the production of non-native phonemes. Methods: Native English speakers were trained on a series of Hindi coronal stop consonants, with production assessed before, during, and after training sessions, on the basis of acoustic cues to place of articulation and voicing. Results: Improvement in production was most apparent during artic u­latory training, when cues to target articulation were available to learners. Some improvements were maintained after training was concluded. Conclusion: Articu­latory training can contribute useful cues to pronunciation for early learners. Improvement in acquisition of targets varies in stability across learners and targets.

Task-free auditory EEG paradigm for probing multiple levels of speech processing in the brain.

While previous studies on language processing highlighted several ERP components in relation to specific stages of sound and speech processing, no study has yet combined them to obtain a comprehensive picture of language abilities in a single session. Here, we propose a novel task-free paradigm aimed at assessing multiple levels of speech processing by combining various speech and nonspeech sounds in an adaptation of a multifeature passive oddball design. We recorded EEG in healthy adult participants, who were presented with these sounds in the absence of sound-directed attention while being engaged in a primary visual task. This produced a range of responses indexing various levels of sound processing and language comprehension: (a) P1-N1 complex, indexing obligatory auditory processing; (b) P3-like dynamics associated with involuntary attention allocation for unusual sounds; (c) enhanced responses for native speech (as opposed to nonnative phonemes) from ∼50 ms from phoneme onset, indicating phonological processing; (d) amplitude advantage for familiar real words as opposed to meaningless pseudowords, indexing automatic lexical access; (e) topographic distribution differences in the cortical activation of action verbs versus concrete nouns, likely linked with the processing of lexical semantics. These multiple indices of speech-sound processing were acquired in a single attention-free setup that does not require any task or subject cooperation; subject to future research, the present protocol may potentially be developed into a useful tool for assessing the status of auditory and linguistic functions in uncooperative or unresponsive participants, including a range of clinical or developmental populations.

Perception and production in interaction during non-native speech category learning.

Establishing non-native phoneme categories can be a notoriously difficult endeavour-in both speech perception and speech production. This study asks how these two domains interact in the course of this learning process. It investigates the effect of perceptual learning and related production practice of a challenging non-native category on the perception and/or production of that category. A four-day perceptual training protocol on the British English /æ/-/ɛ/ vowel contrast was combined with either related or unrelated production practice. After feedback on perceptual categorisation of the contrast, native Dutch participants in the related production group (N = 19) pronounced the trial's correct answer, while participants in the unrelated production group (N = 19) pronounced similar but phonologically unrelated words. Comparison of pre- and post-tests showed significant improvement over the course of training in both perception and production, but no differences between the groups were found. The lack of an effect of production practice is discussed in the light of previous, competing results and models of second-language speech perception and production. This study confirms that, even in the context of related production practice, perceptual training boosts production learning.

Enhanced neural and behavioural processing of a nonnative phonemic contrast in professional musicians.

Based on growing evidence suggesting that professional music training facilitates foreign language perception and learning, we examined the impact of musical expertise on the categorisation of syllables including phonemes that did (/p/, /b/) or did not (/ph /) belong to the French repertoire by analysing both behaviour (error rates and reaction times) and Event-Related brain Potentials (N200 and P300 components). Professional musicians and nonmusicians categorised syllables either as /ba/ or /pa/ (voicing task), or as /pa/ or /ph a/ with /ph / being a nonnative phoneme for French speakers (aspiration task). In line with our hypotheses, results showed that musicians outperformed nonmusicians in the aspiration task but not in the voicing task. Moreover, the difference between the native (/p/) and the nonnative phoneme (/ph /), as reflected in N200 and P300 amplitudes, was larger in musicians than in nonmusicians in the aspiration task but not in the voicing task. These results show that behaviour and brain activity associated to nonnative phoneme perception are influenced by musical expertise and that these effects are task-dependent. The implications of these findings for current models of phoneme perception and for understanding the qualitative and quantitative differences found on the N200 and P300 components are discussed.

Disruption of learning on a non-native phonetic contrast by a brief practice break

What is required for long-lasting learning of a non-native phonetic contrast? Do principles from fine-grained discrimination learning apply? Discrimination learning often requires extensive practice within a day for performance to improve across days, and a 30-minute break midway through practice can disrupt that learning. Thus it appears that trials must integrate to a learning threshold in a transient memory store in order for durable discrimination learning to occur. We asked whether this same principle applies in phonetic-contrast learning. To do so, we trained monolingual speakers on a non-native phonetic contrast along a voice-onset-time (VOT) continuum. Those who engaged in a single continuous practice session on day 1 reached above chance accuracy on day 2 while classifying the non-native phoneme. In contrast, when day-1 practice included a 30-minute break halfway through training, day-2 performance was at chance. These results suggest that for phoneme learning, as for discrimination learning, long-lasting learning requires that practice trials be integrated up to a learning threshold within a transient memory store before they are sent en masse into a memory that lasts across days.