L2 Vowel Perception Research Articles

Unexpected findings from L2 speech research can help us understand how humans process vowels

Research on nonnative speakers’ vowel production and perception has provided us with a number of surprising insights on how learners cope with nonnative vowels. Three of these initially unexpected, yet later solidly replicated, findings will be presented: (1) A decline in intelligibility of nonnative vowels as general proficiency improves (when an increase in intelligibility will be expected), (2) the use of acoustic cues in L2 vowel perception that cannot be attributed to transfer from the native language, and that are nonfunctional in the L2, and (3) the maintenance from infant speech perception in adult cross-language vowel perception of a bias favoring peripheral vowels. This presentation will discuss implications of these findings for our understanding of how vowel categories coexist in the minds of multilinguals, and of universally (native-language independent) preferred ways of vowel perception.

Same vowels but different contrasts: Mandarin listeners’ perception of English /ei/-/iː/ in unfamiliar phonotactic contexts

The study presented here examines how adult L2 listeners’ L1 phonotactics interferes with L2 vowel perception in different consonantal contexts. We examined Mandarin listeners’ perception of the English /ei/-/iː/ vowel contrast in three onset consonantal contexts, /p f w/, which represent different phonotactic scenarios with respect to the permissibility of Mandarin phonology. L1 Mandarin listeners (N = 42) completed a series of three tasks: a categorisation task, a vowel identification task, and an AXB discrimination task. The results show that English /ei/-/iː/ are perceived as highly contrastive in the /p/ context because both /pei/ and /piː/ constitute a licit sequence in Mandarin phonology. However, participants experience substantial /ei/-/iː/ category confusion in the /f/ and /w/ contexts, where Mandarin listeners repair perceptually by modifying the vowel quality in illicit (unattested) consonant–vowel sequences, i.e., */fiː/ → /fei/ and */wiː/ → /wei/. Further exploratory analyses indicate that L2 listeners’ vowel perception in unfamiliar phonotactic contexts is associated with their target language experience, typically indicated by their L2 vocabulary size. The findings thus suggest that the acquisition of novel phonotactic regularities is tied to increased experience with the L2 lexicon.

English vowel perception by non-native speakers: impact of audio and visual training modalities

Perception of sounds of a second language (L2) presents difficulties for non-native speakers which can be improved with training (Bradlow, Pisoni, Akahane-Yamada & Tohkura, 1997; Logan, Lively & Pisoni, 1991; Iverson & Evans, 2009). The aim of this study was to compare three different English vowel perceptual training programmes using audio (A), audiovisual (AV) and video (V) modes in non-native speakers with Spanish as native language (L1). 47 learners of English with Spanish as L1 were allocated to three different vowel training groups (AT, AVT, VT) and were given five training sessions to assess their improvement in English vowel perception. Additionally, participants were recorded before and after training to measure their improvement in the production of English vowels. Results showed that participants improved their perception and production of English vowels regardless of their training modality with no evidence of a benefit of visual information. These results also suggest that there is a lot of individual differences in perception and production of L2 vowels which may be related to a complex relation between speech perceptual and production mechanisms.

Distinctiveness and Assimilation in Vowel Perception in a Second Language.

Purpose The purpose of this study was to investigate how the distinctive establishment of 2nd language (L2) vowel categories (e.g., how distinctively an L2 vowel is established from nearby L2 vowels and from the native language counterpart in the 1st formant [F1] × 2nd formant [F2] vowel space) affected L2 vowel perception. Method Identification of 12 natural English monophthongs, and categorization and rating of synthetic English vowels /i/ and /ɪ/ in the F1 × F2 space were measured for Chinese-native (CN) and English-native (EN) listeners. CN listeners were also examined with categorization and rating of Chinese vowels in the F1 × F2 space. Results As expected, EN listeners significantly outperformed CN listeners in English vowel identification. Whereas EN listeners showed distinctive establishment of 2 English vowels, CN listeners had multiple patterns of L2 vowel establishment: both, 1, or neither established. Moreover, CN listeners' English vowel perception was significantly related to the perceptual distance between the English vowel and its Chinese counterpart, and the perceptual distance between the adjacent English vowels. Conclusions L2 vowel perception relied on listeners' capacity to distinctively establish L2 vowel categories that were distant from the nearby L2 vowels.

Individual Differences in L2 Speech Perception: The Role of Phonological Memory and Lipreading Ability

AbstractThe current study investigated the effects of individual differences in lipreading ability, working memory (WM), and phonological short‐term memory (PSTM) on second language (L2) speech perception. An L2 French vowel identification task was administered to 32 Australian English learners of French in audiovisual, audio‐only, and visual‐only conditions. Participants also completed tasks measuring their first language (L1) lipreading ability at the phoneme, word, and sentence level; a listening span task assessing their WM capacity; and a nonword repetition task assessing their PSTM. Overall, speech perception was significantly better in the audiovisual and audio‐only conditions, and large individual variability was observed in the lipreading, WM, and PSTM tasks. Results revealed a significant effect of PSTM on vowel perception scores in all modalities of presentation, but no effect of WM capacity was found. In addition, lipreading ability at the word level was found to be a predictor of accurate L2 vowel perception in the visual modality.

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.

The determining factor of L2 vowel perception: The establishment of L2 categories

The L2 speech learning theories argue that the perception of L2 phonemes is mainly influenced by the relationship between and among L1 and L2 phonemes. In the present study, we hypothesized that L2 vowel identification is primarily determined by the solidity of the L2 vowel category establishment and the perceptual distance between L2 vowel categories. A group of 31 native Mandarin Chinese-speaking listeners and a control group of 9 native English-speaking listeners participated in the study. All listeners were asked to identify natural English/Chinese vowel identification and categorize and rate synthetic English/Chinese vowels. Major findings include: 1) Chinese learners’ English vowel perception was associated with their capacity to establish English vowel category; 2) the perceptual distance between English vowel contrasts played a key role in Chinese learners’ English vowel perception, rather than the distance between the Chinese vowel and English counterpart. Overall, results of this study suggest that the individual variability of Chinese-native listeners’ English vowel perception is interpreted by the establishment of English vowel categories. [Work supported by China Natural Science Foundation 31628009.]

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.

Speech learning in noise or quiet

Noise made speech perception much more challenging for non-native listeners than for native listeners. We proposed that speech training in noise may better improve non-native listeners’speech perception. In the present study, three groups of native Chinese listeners were trained on English vowel perception under three conditions including quiet (TIQ), noise (TIN), and watching videos in English as an active control (C). Vowel identification in quiet and noise was assessed before, right after training, and three months later after training. Results showed that all listeners significantly improved their vowel identification after training, and the training effect was retained three months later. Compared with the control group, the TIQ group improved more for vowel identification in quiet condition, but not for that in noise conditions. The TIN group improved vowel identification in noise significantly more than the TIQ and control groups. Compared with the TIQ，less informational masking and energetic masking was also found in the post-training test for the TIN than that for the TIQ. These results suggested that vowel perceptual training in noise may better improve L2 vowel perception in adverse acoustic environments than training in quiet. Implications for second language speech perception training were discussed.

Vowel inventory size matters: assessing cue-weighting in L2 vowel perception

To examine whether L1 vowel inventory size could be a contributing factor to the use of temporal cues in L2 vowel perception, this study assessed the perception of English /i-ɪ/ by 66 learners of four different L1s: Danish, Portuguese, Catalan and Russian. The L2 learners performed a forced-choice identification task containing natural and duration-manipulated stimuli. Findings suggest that the participants’ over-reliance on duration cues seem to be partially related to their L1 vowel inventory size. The participants with the greatest L1 vowel inventory (Danish) demonstrated the most native-like vowel perception and the participants with the smallest L1 vowel inventory (Russian) over-relied on duration cues more than the other learners. Interestingly, the participants with somewhat comparable L1 vowel inventories (Portuguese and Catalan) performed similarly.

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.

“Never too late to spot a difference”: the development of L2 speech perception in adults

Abstract Learning correct pronunciation of a second/foreign language always represents a considerable challenge for language learners (e.g. Rojczyk, 2010a), especially for adults (e.g. Flege, 2007). There is an abundance of studies (e.g. Nowacka, 2010; Flege, 1991) showing that second language learners whose first language (L1) phonetic system has only one sound where L2 is characterized by noticeable richness of separate sound categories, encounter serious problems when they try to distinguish those new sounds and, moreover, they tend to apply their native vowels or consonants in L2 speech. It may be easily audible in the case of vowels and actually a lot of studies on L2 learners’ production and perception of L1 and L2 vowels have been carried (e.g. Flege, 1992; Nowacka, 2010; Rojczyk, 2010a; Rojczyk, 2010b). The aim of this study was to examine elementary learners’ perception of 4 German vowels, namely: /ɪ/, /iː/, /ʏ/ and /yː/. They were organized as two sets of minimal pairs, namely /ɪ/ vs. /ʏ/ and /iː/ vs. /yː/. The aforementioned sounds were chosen for the study since /ʏ/ and /yː/ are considered to be very difficult vowels for Polish learners (e.g. Bęza, 2001). Twelve elementary, adult (29-52 years old) Polish learners of German agreed to participate in the study. The subjects had just began their A2-level language course, however they had been taught the basics of German pronunciation for a year, during their A1-level course. They were presented a printed list of word pairs and listened to the recorded words. Then they were asked to circle the right option in each pair. The results revealed that although all study participants were adults when they started learning German and they were still just elementary users of the language, they were already able to distinguish correctly a considerable number of words. It may suggest that proper pronunciation training during a FL/L2 course can provide language learners with measurable benefits.

Predicting and explaining second language speech through individual differences: Insights from testing and extending the Second Language Linguistic Perception model

In this talk, I will present five studies aimed at demonstrating that individual native production and perception abilities predict and explain success in L2 sound perception and word recognition. These studies tested and extended the theoretical and computational framework of the Second Language Linguistic Perception (L2LP) model was tested and extended. The model’s main claim states that accurate predictions for L2 success should be based on individual learners’ native production and perception as well as their responsiveness to rapid perception training. In Study 1, we show how differences in how listeners produce native vowel sounds are predictive of their discrimination accuracy when perceiving L2 vowel contrasts. The predictive power of individual native and L2 vowel perception on the learning of novel L2 words are reported in Studies 2 and 3. Study 4 shows that distributional training, based on the frequency distributions of difficult non-native contrasts, leads to short and long term improvement of difficult non-native contrasts and whether this improvement generalizes the contrasts produced in different contexts and by multiples speakers. Finally, Study 5 tests whether the perception training in Study 4 has short and long term impact on the L2 word learning. A discussion of the findings and their implications for the L2LP proposal and that of other models of L2 speech will be presented.

Spectral dynamics in L1 and L2 vowel perception

This paper presents a study of L1 and L2 vowel perception by Polish learners of English. Employing the Silent Center paradigm (e.g. Strange et al. 1983), by which listeners are presented with different portions of a vowel, a force choice identification task was carried out. Due to differences in the vowel systems of the two languages, it was hypothesized that stimulus type should have minimal effects for L1 Polish vowel perception since Polish vowels are relatively stable in quality. In L2 English, depending on proficiency level, listeners were expected to adopt a more dynamic approach to vowel identification and show higher accuracy rates on the SC tokens. That is, listeners were expected to attend more to dynamic formant cues, or vowel inherent spectral change (VISC; see e.g. Morrison and Assmann 2013) in vowel perception. Results for identification accuracy for the most part were consistent with these hypotheses. Implications of VISC for the notion of cross-language phonetic similarity, crucial to models of L2 speech acquisition, are also discussed.

Estimating Korean EFL listeners’ perception of English vowels with reference to cross-language labelling

This paper explores whether Korean EFL listeners perception of English vowels and their English vowel category development can be estimated from cross-language labelling between English and Korean. The paper also investigates whether cross-language labelling makes different predictions for General American English (GAE) vowels and British English (Received Pronunciation, RP) vowels, given that vowel category variation exists between the two accents. Thirty-six university students in Seoul completed cross-language labelling and English vowel identification. Fit indices were calculated based on cross-language labelling for both GAE and RP vowels in order to answer the questions posed. Specifically, the paper tested the assumption of the Speech Learning Model (SLM) that L2 category development is closely related to the perceived phonetic distance between L1 and L2 sounds by calculating fit indices. The results reveal that the fit indices computed had limitations in accounting for the identification accuracy of L2 vowels. The fit indices also made similar predictions for GAE and RP vowels, but there were accent and vowel category variations between GAE and RP. Thus, the overall results suggest that L2 vowel perception or L2 vowel category learning depends on factors such as L2 learners’ target language accent and their overall interlanguage phonological system, as well as the perceived phonetic distance between an L2 sound and its closest L1 counterpart.

The effect of L1 regional variation on the perception and production of standard L1 and L2 vowels

AbstractThis study reports on the perception and production of Standard Dutch and Standard British English vowels by speakers of two regional varieties of Belgian Dutch (East Flemish and Brabantine) which differ in their vowel realizations. Twenty-four native speakers of Dutch performed two picture-naming tasks and two vowel categorization tasks, in which they heard Standard Dutch or English vowels and were asked to map these onto orthographic representations of Dutch vowels. The results of the Dutch production and categorization tasks revealed that the participants’ L1 regional variety importantly influenced their production and especially perception of vowels in the standard variety of their L1. The two groups also differed in how they assimilated non-native English vowels to native vowel categories, but no major differences could be observed in their productions of non-native vowels. The study therefore only partly confirms earlier studies showing that L1 regional variation may have an influence on the acquisition of non-native language varieties.

Native dialect influences second-language vowel perception: Peruvian versus Iberian Spanish learners of Dutch

Peruvian Spanish (PS) and Iberian Spanish (IS) learners were tested on their ability to categorically discriminate and identify Dutch vowels. It was predicted that the acoustic differences between the vowel productions of the two dialects, which compare differently to Dutch vowels, would manifest in differential L2 perception for listeners of these two dialects. The results show that although PS learners had higher general L2 proficiency, IS learners were more accurate at discriminating all five contrasts and at identifying six of the L2 Dutch vowels. These findings confirm that acoustic differences in native vowel production lead to differential L2 vowel perception.

VOCABULARY SIZE IS ASSOCIATED WITH SECOND-LANGUAGE VOWEL PERCEPTION PERFORMANCE IN ADULT LEARNERS

Improvement in second-language (L2) perception has been posited to occur early in L2 learning when the L2 vocabulary is still small, whereas a large L2 vocabulary curtails perceptual learning (the perceptual assimilation model for SLA [PAM-L2]; Best & Tyler, 2007). This proposition is extended by suggesting that early L2 lexical development facilitates the establishment of phonological categories in a manner analogous to children’s first-language (L1) acquisition before as opposed to after the vocabulary spurt. According to this view, L2 speech should be assimilated more consistently to L1 phonological categories and cross-boundary contrasts should be discriminated more accurately by learners with larger L2 vocabularies. To test this proposition, a novel whole-system approach to evaluate perception of L2 vowels in two experiments was applied. In Experiment 1, Japanese learners of Australian English (AusE) with less than 12 weeks of L2 learning in Australia completed labeling and goodness ratings on all AusE vowels, selecting from among all monomoraic and bimoraic Japanese vowels and vowel combinations. They also discriminated four L2 vowel contrasts, representing a range of PAM-L2 contrast types, and completed a L2 vocabulary size assessment. Learners with larger vocabularies had more consistent L2-L1 vowel assimilation and more accurate cross-boundary discrimination than those with smaller vocabularies, supporting the proposition that lexical development assists L2 phonological acquisition. Experiment 2 compared the perception of AusE vowels by Japanese learners after only 4–8 weeks in Australia with their perception after 6–8 months of L2 exposure. The results also supported the predicted positive association between L2 vocabulary size and L2 vowel perception rather than a general prediction of increased exposure duration leading to improved perception.

Explaining individual variation in L2 perception: Rounded vowels in English learners of German

Most empirical research in L2 vowel perception focuses on the development of groups of learners. However, recent studies indicate that individual learners' developmental paths in L2 vowel perception may not be uniform (e.g., Escudero, 2001; Escudero and Boersma, 2004; Morrison, 2009). The aim of the present study is to add to this line of research by investigating (1) whether individual English learners of German follow different paths in their perceptual development of six rounded German vowels, and (2) whether the observed patterns are explicable on the basis of Escudero's (2005)Second-Language Linguistic Perception(L2LP) model. A cross-language perceptual assimilation experiment revealed that learners’ assimilation of L2 sounds to native categories is indeed highly diverse, yet systematic. Importantly, these cross-language mapping patterns largely predict the learners’ further development in L2 vowel perception, as assessed in a forced-choice identification task. Implications for explanatory frameworks in second-language speech research are discussed.

Increased second‐language vocabulary size is associated with more consistent second‐language vowel categorization and better discrimination.

Improvement in second‐language (L2) perception has been posited to asymptote early in L2 learning when the L2 vocabulary is still small, whereas a large L2 vocabulary curtails perceptual learning [PAM‐L2: Best and Tyler (2007)]. We extend this proposition by suggesting that early L2 lexical development facilitates establishment of phonological categories in a manner analogous to toddlers’ L1 acquisition before versus after the vocabulary explosion. According to this revised view, L2 speech should be assimilated more consistently to phonological categories, and cross‐boundary contrasts discriminated more accurately, by learners with large versus small L2 vocabularies. We applied a novel whole‐system approach to evaluate perception of L2 vowels with respect to the L1 vowel system. Japanese learners of Australian English with under 12 weeks of L2 immersion completed labeling and goodness ratings on all Australian vowels, using all mono‐ and bi‐moraic Japanese vowels and vowel combinations. They also completed discrimination tasks on four L2 vowel contrasts, representing a range of PAM‐L2 contrast types, and a L2 vocabulary size assessment. Learners with larger vocabularies had more consistent vowel assimilation and more accurate cross‐boundary discrimination than those with smaller vocabularies, supporting the proposition that lexical development supports L2 phonological acquisition. [Work supported by NIH and MARCS/UWS.]