Vowel Categories Research Articles

Vowel categorization accuracy and its relationship to phonemic awareness

Cross-language speech perception studies regularly employ categorization tasks to determine listeners’ repertoire of phonological categories. In these tasks, participants select a phoneme from a list of letters or keywords to indicate which speech category they heard. However, recent studies have shown poor categorization accuracy when native (L1) English speakers are asked to categorize English vowels. Categorization tasks require phonemic awareness (PA), the explicit knowledge that words consist of segments, which is acquired alongside alphabetic literacy. Individual differences in PA may account for variability in L1 categorization accuracy. That is, participants with poor phonemic awareness may have difficulty explicitly identifying phonemes in a categorization task, particularly for English vowels, where grapheme-phoneme correspondences are relatively opaque. To test whether PA is related to categorization accuracy, 115 L1 English listeners completed an L1 vowel categorization task and three PA tasks: phoneme counting, deletion, and reversal. Strong correlations were observed between categorization accuracy and all three PA tasks, suggesting PA may account for a substantial proportion of individual variability in vowel categorization tasks. This finding questions the utility of the categorization task for determining listeners’ phonemic categories and has further implications for assessing second language speech categories.

Medium-shifting and intraspeaker variation in conversational interviews

AbstractWe investigate the impact of medium of communication (in-person versus video) on intraspeaker variation in conversation—a process we refer to asmedium-shifting. To quantify the effects of medium-shifting and understand its possible motivations, we analyze three variables that show intraspeaker effects of “clear” or “careful” speech: articulation rate, density-controlled vowel space area, and (ING). The data come from matched in-person and video-mediated interviews with thirty-three repeat guests fromThe Late Show with Stephen Colbert, recorded before and during the COVID-19 pandemic. Mixed-effects regression models show that compared to in-person interviews, video-mediated interviews involve a significantly lower articulation rate and larger vowel space, but no significant difference in (ING). The results suggest that speakers may engage in medium-shifting in order to enhance their intelligibility over video, for example, through more precise articulatory movements and greater contrast between phonemic vowel categories. The null effect of medium on (ING) further suggests that medium-shifting is a motivator of intraspeaker differences even within a single contextual style. An emergent extralinguistic factor affecting speaking behavior and choices, medium-shifting should be carefully considered especially when designing variationist research involving mixed media interviews.

Learning on the Field: L2 Turkish Vowel Production by L1 American English-Speaking NGOs in Turkey

This study adopts the Speech Learning Model to investigate the first language (L1) influence as well as the effects of the length of residence and second language (L2) exposure on American English-speaking learners of Turkish in their productions of Turkish unrounded–rounded vowel pairs, with a particular focus on the vowel categories “new” to American English speakers (/y/, /œ/, and /ɯ/). L1 (English) and L2 (Turkish) speech samples were collected from 18 non-governmental organisation (NGO) workers. L2 experience was defined by whether the worker lived in an urban or regional environment in Turkey. Participants’ audio productions of the word list in L1 and L2 were segmented and annotated for succeeding acoustic analyses. The results show an interesting front–back variability in the realisations of the three vowels, including further back variants of the front vowels (/y/, /œ/) and more forward variants of the /ɯ/ vowel, with a substantial degree of interspeaker variability. While the analysis revealed no significant results for the length of residence, language experience was found to have a significant effect on the production of /y/ (F2) and /ɯ/ (F1/F2). This study forms a first step into the research of adult L2 acquisition in Turkish with a focus on L2 in the naturalistic workplace environment, rather than instructed settings. The findings of this study will contribute to the development of teaching materials for NGO workers learning Turkish as their L2.

Operation LiLi: Using Crowd-Sourced Data and Automatic Alignment to Investigate the Phonetics and Phonology of Less-Resourced Languages

Less-resourced languages are usually left out of phonetic studies based on large corpora. We contribute to the recent efforts to fill this gap by assessing how to use open-access, crowd-sourced audio data from Lingua Libre for phonetic research. Lingua Libre is a participative linguistic library developed by Wikimedia France in 2015. It contains more than 670k recordings in approximately 150 languages across nearly 740 speakers. As a proof of concept, we consider the Inventory Size Hypothesis, which predicts that, in a given system, variation in the realization of each vowel will be inversely related to the number of vowel categories. We investigate data from 10 languages with various numbers of vowel categories, i.e., German, Afrikaans, French, Catalan, Italian, Romanian, Polish, Russian, Spanish, and Basque. Audio files are extracted from Lingua Libre to be aligned and segmented using the Munich Automatic Segmentation System. Information on the formants of the vowel segments is then extracted to measure how vowels expand in the acoustic space and whether this is correlated with the number of vowel categories in the language. The results provide valuable insight into the question of vowel dispersion and demonstrate the wealth of information that crowd-sourced data has to offer.

The Categorization of L3 Vowels Near First Exposure by Spanish-English Bilinguals

The present study examined the predictions the Perceptual Assimilation Model in the context of naïve bilingual speakers while also considering whether the predictions of third language (L3) models of morphosyntax could be extended to L3 phonology. In particular, it was asked whether several groups of Spanish-English bilinguals (constituting a fully combined design) would categorize sounds in two unknown languages, French and German, using their first language (L1) categories, second language (L2) categories, or a combination of both. 199 participants took part in the study, who made up 4 total groups: L1 English–L2 Spanish (n = 55), L1 Spanish–L2 English (n = 59), English monolingual (n = 59) and Spanish monolingual (n = 29). The participants completed a vowel categorization task, where they were asked to match four vowel sounds in French and German to their existing English and Spanish categories. The results of a series of Bayesian Multinomial regression models suggested that bilinguals categorize L3 vowels using both L1 and L2 categories according to the acoustics of the input. There was no evidence of a clear bias for either the L1 or L2 when an L3 vowel exists in both the L1 and L2. Additionally, the bilingual English participants differed from English monolinguals in the their categorization of new language sounds. These results have implications for both the PAM-L2 and L3 models, by showing that the language learners are not solely guided by their native language, and have access to both L1 and L2 categories when accounting for novel language sounds.

Context effects in perception of vowels differentiated by F1 are not influenced by variability in talkers' mean F1 or F3.

Spectral properties of earlier sounds (context) influence recognition of later sounds (target). Acoustic variability in context stimuli can disrupt this process. When mean fundamental frequencies (f0's) of preceding context sentences were highly variable across trials, shifts in target vowel categorization [due to spectral contrast effects (SCEs)] were smaller than when sentence mean f0's were less variable; when sentences were rearranged to exhibit high or low variability in mean first formant frequencies (F1) in a given block, SCE magnitudes were equivalent [Assgari, Theodore, and Stilp (2019) J. Acoust. Soc. Am. 145(3), 1443-1454]. However, since sentences were originally chosen based on variability in mean f0, stimuli underrepresented the extent to which mean F1 could vary. Here, target vowels (/ɪ/-/ɛ/) were categorized following context sentences that varied substantially in mean F1 (experiment 1) or mean F3 (experiment 2) with variability in mean f0 held constant. In experiment 1, SCE magnitudes were equivalent whether context sentences had high or low variability in mean F1; the same pattern was observed in experiment 2 for new sentences with high or low variability in mean F3. Variability in some acoustic properties (mean f0) can be more perceptually consequential than others (mean F1, mean F3), but these results may be task-dependent.

Musical experience partially counteracts temporal speech processing deficits in putative mild cognitive impairment.

Mild cognitive impairment (MCI) commonly results in more rapid cognitive and behavioral declines than typical aging. Individuals with MCI can exhibit impaired receptive speech abilities that may reflect neurophysiological changes in auditory-sensory processing prior to usual cognitive deficits. Benefits from current interventions targeting communication difficulties in MCI are limited. Yet, neuroplasticity associated with musical experience has been implicated in improving neural representations of speech and offsetting age-related declines in perception. Here, we asked whether these experience-dependent effects of musical experience might extend to aberrant aging and offer some degree of cognitive protection against MCI. During a vowel categorization task, we recorded single-channel electroencephalograms (EEGs) in older adults with putative MCI to evaluate speech encoding across subcortical and cortical levels of the auditory system. Critically, listeners varied in their duration of formal musical experience (0-21 years). Musical experience sharpened temporal precision in auditory cortical responses, suggesting that musical experience produces more efficient processing of acoustic features by counteracting age-related neural delays. Additionally, robustness of brainstem responses predicted the severity of cognitive decline, suggesting that early speech representations are sensitive to preclinical stages of cognitive impairment. Our results extend prior studies by demonstrating positive benefits of musical experience in older adults with emergent cognitive impairments.

Repetitive Exposure to Orofacial Somatosensory Inputs in Speech Perceptual Training Modulates Vowel Categorization in Speech Perception.

Orofacial somatosensory inputs may play a role in the link between speech perception and production. Given the fact that speech motor learning, which involves paired auditory and somatosensory inputs, results in changes to speech perceptual representations, somatosensory inputs may also be involved in learning or adaptive processes of speech perception. Here we show that repetitive pairing of somatosensory inputs and sounds, such as occurs during speech production and motor learning, can also induce a change of speech perception. We examined whether the category boundary between /ε/ and /a/ was changed as a result of perceptual training with orofacial somatosensory inputs. The experiment consisted of three phases: Baseline, Training, and Aftereffect. In all phases, a vowel identification test was used to identify the perceptual boundary between /ε/ and /a/. In the Baseline and the Aftereffect phase, an adaptive method based on the maximum-likelihood procedure was applied to detect the category boundary using a small number of trials. In the Training phase, we used the method of constant stimuli in order to expose participants to stimulus variants which covered the range between /ε/ and /a/ evenly. In this phase, to mimic the sensory input that accompanies speech production and learning in an experimental group, somatosensory stimulation was applied in the upward direction when the stimulus sound was presented. A control group (CTL) followed the same training procedure in the absence of somatosensory stimulation. When we compared category boundaries prior to and following paired auditory-somatosensory training, the boundary for participants in the experimental group reliably changed in the direction of /ε/, indicating that the participants perceived /a/ more than /ε/ as a consequence of training. In contrast, the CTL did not show any change. Although a limited number of participants were tested, the perceptual shift was reduced and almost eliminated 1 week later. Our data suggest that repetitive exposure of somatosensory inputs in a task that simulates the sensory pairing which occurs during speech production, changes perceptual system and supports the idea that somatosensory inputs play a role in speech perceptual adaptation, probably contributing to the formation of sound representations for speech perception.

Evaluating the learnability of vowel categories from infant-directed speech

Hyper-articulated vowels are considered a hallmark of infant-directed Speech (IDS) and are thought to facilitate acquisition. Consistent with this idea, vowels in IDS are reported to be more peripheral than in adult-directed speech (ADS) (e.g., Trainor and Desjardins, 2002; Liu et al., 2005). However, there are also reports that vowels in IDS are more variable (Cristia and Seidl, 2014; Martin et al., 2015). We evaluated the learnability of vowel categories from IDS in two languages—American English, which has a crowded vowel space, and Mexican Spanish, which has fewer vowels. First, we used k-means clustering, an unsupervised learning algorithm, to partition vowels based on spectral and duration measures from conversational IDS. The algorithm was trained on IDS from 5 English speakers (Providence Corpus, Demuth et al., 2006) and 12 Spanish speakers (Aly et al., 2016). The vowel categories extracted from IDS were used to classify ADS vowels from 5 English speakers from the Buckeye corpus and 12 Spanish speakers (Kim and Repiso Puigderlliura, 2021). Next, we switched the training and testing set, by training on ADS, and testing on IDS. If IDS is facilitative, we expect a higher accuracy of vowel classification with training on IDS rather than ADS.

Influences of talker gender on second language speech perception

This study examined how talker gender information may influence second language speech perception. The participants were ten right-handed male Japanese adults with normal hearing. The speech stimuli were two minimal pairs of English words, “heed-hod” and “head-had”, recorded from twenty male and twenty female native English speakers. The stimuli were delivered binaurally at a sensation level of 50 dB. In the gender recognition task, the subjects were asked to judge talker gender. In the vowel recognition task, they were asked to identify the vowel category. Magnetoencephalography data were recorded during the experiment. For gender recognition, there was no significant difference in identification accuracy between the two word pairs while reaction time was significantly faster for the difficult “head-had” pair. In the phoneme recognition task, there was a significant phoneme*gender interaction for the difficult “head-had” pair but not for the easy “heed-hod” pair. The MEG data for gender recognition showed right hemisphere dominance, and the phoneme recognition task showed overall bilateral activation. Time-frequency analysis further revealed distinctions between male and female voices and the difficulty differences for the two word pairs in the phoneme recognition task. The results suggest a complex role of paralinguistic gender information in L2 speech perception.

Noise helps cochlear implant listeners to categorize vowels.

Theoretical studies demonstrate that controlled addition of noise can enhance the amount of information transmitted by a cochlear implant (CI). The present study is a proof-of-principle for whether stochastic facilitation can improve the ability of CI users to categorize speech sounds. Analogue vowels were presented to CI users through a single electrode with independent noise on multiple electrodes. Noise improved vowel categorization, particularly in terms of an increase in information conveyed by the first and second formant. Noise, however, did not significantly improve vowel recognition: the miscategorizations were just more consistent, giving the potential to improve with experience.

Later but Not Weaker: Neural Categorization of Native Vowels of Children at Familial Risk of Dyslexia

Although allophonic speech processing has been hypothesized to be a contributing factor in developmental dyslexia, experimental evidence is limited and inconsistent. The current study compared the categorization of native similar sounding vowels of typically developing (TD) children and children at familial risk (FR) of dyslexia. EEG response was collected in a non-attentive passive oddball paradigm from 35 TD and 35 FR Dutch 20-month-old infants who were matched on vocabulary. The children were presented with two nonwords “giep” [ɣip] and “gip” [ɣIp] that contrasted solely with respect to the vowel. In the multiple-speaker condition, both nonwords were produced by twelve different speakers while in the single-speaker condition, single tokens of each word were used as stimuli. For both conditions and for both groups, infant positive mismatch response (p-MMR) was elicited, and the p-MMR amplitude was comparable between the two groups, although the FR children had a later p-MMR peak than the TD children in the multiple-speaker condition. These findings indicate that FR children are able to categorize speech sounds, but that they may do so in a more effortful way than TDs.

Production, Perception and Identification of English and Arabic Vowels and Semi-vowels by Iraqi Arabic EFL Learners

The recent paper centers on reporting the error in the production, perception and identification of segmental phonemes of both Arabic and English. Formerly Arabic learners may come across many difficulties in the recognition and pronunciation a foreign language, such as English, due to the enormous variations, principally, in vowels and consonants inventory and their acoustic realizations. It also examines gender influence on learners' performance in three tasks. The total number of subjects are (36) Iraqi EFL learners; categorized into six groups based on their education proficiency levels. MP3 recording device is used in the tasks to record learners' pronunciation. The list of tested words contains (20) words that exemplify simple, long vowels and semi vowels. The results revealed that most Iraqi L2 learners have problems in articulating short and long English vowels and they come across fluctuating gradations of difficulty. The results also show that there is an effect of the level of education on the accuracy rate for some vowel categories. The most problematic vowels were /ɒ, ʌ, ɔ: / which were difficult for most subjects regardless their education level and proficiency in English.

Bibliography (in English) for 2020

Bibliography (in English) for 2020 David Bratman (bio) Primary Sources Tolkien, J.R.R. [Letters to Mary Fairburn, 24 May and 4 Sept. 1968]. Borne on the Wind: Memoirs of an Artist. By Mary Fairburn. Castlemaine [Vic.]: Kelly & Rose, 2020. 320, [436–37]. ———, trans. Sir Gawain and the Green Knight, Pearl and Sir Orfeo. Ed. Christopher Tolkien. Rev. ed. London: HarperCollins, 2020. Books Cirilla, Anthony G., and Vincent E. Rone, ed. Mythopoeic Narrative in The Legend of Zelda. New York: Routledge, 2020. Doyle, Mark. Utopian and Dystopian Themes in Tolkien's Legendarium. Lanham, MD: Lexington Books, 2020. Garth, John. The Worlds of J.R.R. Tolkien: The Places that Inspired Middle-earth. Princeton: Princeton UP, 2020. Glyer, Diana Pavlac, ed. Journey Back Again: Reasons to Revisit Middle-earth. Azusa, CA: Azusa Pacific University, Honors College, 2020. ———. A Merrier World: Unsung Virtues in Tolkien's Middle-earth. Azusa, CA: Azusa Pacific University, Honors College, 2020. Halsall, Michael John. Creation and Beauty in Tolkien's Catholic Vision: A Study in the Influence of Neoplatonism in J.R.R. Tolkien's Philosophy of Life as "Being and Gift." Eugene, OR: Lutterworth Press, 2020. Hilder, Monika B., Sara L. Pearson, and Laura N. Van Dyke, ed. The Inklings and Culture: A Harvest of Scholarship from the Inklings Institute of Canada. Newcastle upon Tyne: Cambridge Scholars, 2020. Hooker, Mark T. Tolkienian Glôssology: Or a Study of the Primitive Elvish Vocabulary of Tolkien's Qenya Lexicon and Gnomish Lexicon from the Late 1910s, the Precursors of Quenya and Sindarin. North Haven, CT: Llyfrawr, 2020. Jahosky, Michael T. The Good News of the Return of the King: The Gospel in Middle-earth. Eugene, OR: Wipf & Stock, 2020. McBride, Sam. Tolkien's Cosmology: Divine Beings and Middle-earth. Kent, OH: Kent State UP, 2020. Neubauer, Łukasz, ed. Middle-earth, or There and Back Again. Zurich: Walking Tree, 2020. Snyder, Christopher A. Hobbit Virtues: Rediscovering Virtue Ethics through J.R.R. Tolkien's The Hobbit and The Lord of the Rings. New York: Pegasus, 2020. Vink, Renée. Gleanings from Tolkien's Garden: Selected Essays. Beverwijk [Netherlands]: IJmond, 2020. Widdicombe, Toby. J.R.R. Tolkien: A Guide for the Perplexed. London: Bloomsbury Academic, 2020. Articles and Book Chapters Abalea, Gaelle. "Death as a Gift in J.R.R. Tolkien's Work and Buffy the Vampire Slayer." Journal of Tolkien Research 10.1 (2020). Alvarez, Carla. "Melchizedek, Bombadil, and the Numinous in The Lord of the Rings." An Unexpected Journal 3.1 (Spring 2020): 75–92. Anderson, Brendan. "The Girl in the Woods: "On Fairy Stories" and the Virgin Horror." Journal of Tolkien Research 10.1 (2020). Anderson, Douglas A. "Index to The Journal of Tolkien Research, Volume 1 through Volume 9 issue 1." Journal of Tolkien Research 9.2 (2020). Annear, Lucas. "Vowel Category and Meanings of Size in Tolkien's Early Lexicons." Journal of Tolkien Research 9.2 (2020). Armstrong, Jensen. "A Narrative Quest." Glyer, Journey 19–41. Badger, Keith. "In Search of Bombadil: Tracking J.R.R. Tolkien's Keeper of the Forest." Parabola 45.3 (Fall 2020): 103–9. Beal, Jane. "Saint Galadriel? J.R.R. Tolkien as the Hagiographer of Middle-earth." Journal of Tolkien Research 10.2 (2020). Beech, Martin. "In the Moon Gleaming." Mallorn 60 (Summer 2020): 24–27. Birks, Annie. "Game of Thrones Seen through the Prism of Tolkien's Theory on Fairy Stories." Hither Shore 14 (2017 [2020]): 235–49. Blackham, Bob. "Tolkien in King's Heath." Mallorn 61 (Winter 2020): 35–37. Błaszkiewicz, Bartłomiej. "On the Concept of Hope in the Work of J.R.R. Tolkien." Kwartalnik Neofilologiczny 67 (Jan. 2020): 23–39. ———. "J.R.R. Tolkien's The Fall of Arthur in the Context of the Medieval Tradition of Romance." Neubauer 71–82. Borowiec, Łukasz. "From Wilderland to East End and Back Again: On the Links Between Harold Pinter's The Dwarfs: A Novel and J.R.R. Tolkien's The Hobbit." Roczniki Humanistyczne 68.11 (2020): 65–80. Bowman, Nathaniel. "Courage." Glyer, Merrier 137–51. Boyd, Craig A. "Augustine, Aquinas, & Tolkien: Three Catholic Views on Curiositas." Heythrop Journal 61.2 (Mar. 2020): 222–33. Bradley, Jacob L. "Providence...

A new multi-stream approach using acoustic and visual features for robust speech recognition system

Building a robust Automatic Speech Recognition (ASR) system and improving recognition accuracy in adverse conditions is still a challenging task. One way to improve the robustness of an ASR system is combining information from multiple sources (streams). A multi-stream approach which handles the multiple inputs at the model level is the key contribution of our work. Standard mic (Sm), Throat mic (Tm), and Lip reading (Lr) are the various source streams that have been used. This work explores a static weighted two stream HMM (TSH) and multi-stream HMM (MSH) model for the bimodal and multimodal systems. A syllabic units of the Hindi language database categorized into three categories – Vowel, Place of Articulation (POA), and Manner of Articulation (MOA) are used for training and testing. In this study, four types of TSH are proposed for the combination of bimodal ((Sm+Tm), (Tm+Lr), (Sm+Lr), (Lm+Lm)) systems and one type MSH is proposed for multimodal (Sm+Tm+Lr) system in a synchronous and asynchronous manner. Mel Frequency Cepstral Coefficient (MFCC) features are used for Sm and Tm signals. Combined pixel-motion based features (DCT/DWT-MHI) are used for Lr signals. Among these two features, DWT outperforms than DCT and used as a feature for visual speech. Experiments were conducted for bimodal and multimodal system. The proposed MSH approach shows improvements of 1.36%, 6.21%, and 5.8% in recognition accuracy for Vowel, POA and MOA category respectively, as compared to bimodal systems.

Vowel Production in Aphasia: Preliminary Acoustic Findings from Arabic

The present study examined the temporal and spectral characteristics of vowels produced by Palestinian Arabic- speaking individuals with Broca’s aphasia compared to healthy speakers. Specifically, vowel duration and formant frequency measures (F1&F2) were made. eight speakers with Broca’s aphasia and eight healthy speakers participated in the study. Repetition was used to elicit the target vowels to minimize language comprehension or reading difficulties by the individuals with Broca’s aphasia. The speech sample contains the long vowels (/a:,u:,i:/) embedded in CVC words with nasal initials. Statistical analysis was used to determine any significant differences concerning the formant values (F1/F2) between the speaker groups. Findings showed that speakers with Broca’s aphasia produced vowel categories with more variability than healthy speakers. For some, formant frequencies were comparable with those of the healthy speakers, and yet others showed an overlap of phonetic categories. Specifically, F1 and F2 for the vowel /u:/ were higher for individuals with Broca’s aphasia compared to normal-speaking individuals, but they were not statistically significant. Furthermore, although speakers with Broca’s aphasia produced longer vowel durations than the healthy speakers, they were not significantly different between speaker groups except for the vowel /i:/. Reduced vowel space was also observed in speakers with Broca’s aphasia. The vowel ellipses as shown by speakers with Broca’s aphasia were larger than those of healthy speakers. Results support previous studies showing abnormal temporal durations and spectral patterns in Broca’s aphasia. Findings can contribute to cross-linguistic research on vowel production in aphasia, mainly in understudied languages such as Arabic.

이집트인 학습자의 한국어 모음 지각과 산출*

This study aims to discuss how Egyptian learners of Korean perceive and categorize Korean vowels, how Koreans perceive Korean vowels they pronounce, and how Egyptian learners’ Korean vowel categorization affects their perception and production of Korean vowels. In Experiment 1, 53 Egyptian learners were asked to listen to Korean test words pronounced by Koreans and choose the words they had listened to among 4 confusable words. In Experiment 2, 117 sound files (13 test words×9 Egyptian learners) recorded by Egyptian learners were given to Koreans and asked to select the words they had heard among 4 confusable words. The results of the experiments show that “new” Korean vowels that do not have categorizable ones in Egyptian Arabic easily formed new categories and were therefore well identified in perception and relatively well pronounced, but some of them were poorly produced. However, Egyptian learners poorly distinguished “similar” Korean vowels in perception, but their pronunciation was relatively well identified by native Koreans. Based on the results of this study, we argued that the Speech Learning Model (SLM) and Perceptual Assimilation Model (PAM) explain the L2 speech perception well, but they are insufficient to explain L2 speech production and therefore need to be revised and extended to L2 speech production.

Newborns’ neural processing of native vowels reveals directional asymmetries

Prenatal learning of speech rhythm and melody is well documented. Much less is known about the earliest acquisition of segmental speech categories. We tested whether newborn infants perceive native vowels, but not nonspeech sounds, through some existing (proto-)categories, and whether they do so more robustly for some vowels than for others. Sensory event-related potentials (ERP), and mismatch responses (MMR), were obtained from 104 neonates acquiring Czech. The ERPs elicited by vowels were larger than the ERPs to nonspeech sounds, and reflected the differences between the individual vowel categories. The MMRs to changes in vowels but not in nonspeech sounds revealed left-lateralized asymmetrical processing patterns: a change from a focal [a] to a nonfocal [ɛ], and the change from short [ɛ] to long [ɛ:] elicited more negative MMR responses than reverse changes. Contrary to predictions, we did not find evidence of a developmental advantage for vowel length contrasts (supposedly most readily available in utero) over vowel quality contrasts (supposedly less salient in utero). An explanation for these asymmetries in terms of differential degree of prior phonetic warping of speech sounds is proposed. Future studies with newborns with different language backgrounds should test whether the prenatal learning scenario proposed here is plausible.

Maintenance of phonetic and phonological distance in the English and Korean back vowel contours of heritage bilinguals

Bilingualism research demonstrates that the potential merger of vowel categories across a speaker’s two languages is affected by the age of acquisition of the second language. For heritage bilinguals, however, there is no clear L1 and L2, since they acquire their heritage language in early childhood, but become dominant in the mainstream language of society as adults. Heritage bilinguals may nevertheless will acquire distinct vowel systems in their two languages, rather than a merged system. In this study, the back vowels of California English and Seoul Korean, two varieties that are spoken by bilingual second-generation Korean Americans in California, were collected in natural speech. Formant measurements were analyzed using linear mixed effects regression modeling and generalized additive mixed modeling to see whether the vowels of each language were similar or different in their formant contours. As predicted, the bilinguals maintained distance between the vowels of both languages across their durations, and the phonological effects of coarticulation were found to be stronger in English than in Korean. The differences are attributed to “multicompetence” in heritage bilinguals’ phonology (Cook, 2020), or the interrelationship of multiple systems that exist and interact in the bilingual mind without merging completely, in opposition to models that frame heritage bilingualism as inherently imbalanced in favor of the dominant language.

Acoustic influence of L1 Spanish on L2 English vowel production

The strength of influence of the L1 vowel inventory on L2 vowel acquisition is well-documented: learners who identify an L2 phoneme as belonging to an L1 category may fail to establish a distinct category for the new phoneme (Flege, 2002), while those who establish a new category for an L2 vowel may ultimately exhibit more native-like pronunciation (Bohn & Flege, 1992). In learning an L2 with many more vowel categories than the L1, as Spanish-English bilinguals must, speaker-specific category assimilation and discrimination are important contributors to the level of accentedness and intelligibility. This study examines the influence of L1 vowels on L2 production via formants and duration of stressed and unstressed L1 Spanish/L2 English vowels. Ten advanced Spanish-English bilinguals completed a shadowing task in both languages, producing five vowels from each language in various target words. Examined in the aggregate, most vowels remained spectrally distinct along both the F1 and F2 dimensions, with a few categories collapsed across one dimension or the other; unstressed vowels raised in both languages, but raised further in English than Spanish. However, interspeaker differences in the patterns of category assimilation necessitate an individual analysis, highlighting the high level of variation in acquisition across individuals.