Target Vowel Research Articles

Individual Variability in the Production of /e/ and /ɛ/ in Yanbian Korean

This study investigates the production of two vowels (/e/ and /ɛ/) in Yanbian Korean to determine whether Yanbian Korean speakers produce the two vowels similarly. This was achieved by directly comparing the vowel production of Yanbian Korean to the control data provided by speakers of Seoul Korean, a dialect where an unconditional merger of the two vowels is already complete. We hypothesized that speakers in close contact with Seoul Korean speakers tend to neutralize the distinction between the two vowels. Resutls from the two statistical analyses (Pillai and Bhattacharyya’s affinity) confirmed that Seoul Korean speakers display completely overlapping distribution of the vowels, whereas Yanbian Korean speakers showed greater individual variability when producing the same vowels. Some speakers, who had constant contact with Seoul Korean speakers at work or school, produced the target vowels in a similar fashion; however, others clearly produced them as different phonemes. The results suggest that direct or prolonged contact with or exposure to a dominant language may play a role in initiating the spread of the merger at an individual level.

Pterygoid muscle activity in speech: A preliminary investigation.

Speaking depends on refined control of jaw opening and closing movements. The medial pterygoid muscle (MPT), involved in jaw closing, and the lateral pterygoid muscle (LPT), involved in jaw opening, are two key mandibular muscles in mastication and are likely to be recruited for controlled movements in speech. Three hypotheses were investigated, that during speech the MPT and LPT: (1) were both active, (2) but exhibited different patterns of activity, (3) which fluctuated with the vowels and consonants in speech. Intramuscular EMG recordings were made from the right inferior head of the LPT and/or the right MPT in five participants during production of 40 target nonsense words (NWs) consisting of three syllables in the form /V1 C1 V2 C2 ə/ (V=vowel; C=consonant; ə=unstressed, reduced vowel), spoken by each participant 10 times per NW; analysis focussed on the target syllable, C1 V2 . Both MPT and LPT exhibited robust increases in EMG activity during utterance of most NWs, relative to rest. Peak LPT activation was time-locked to the final part of the target consonant (C1 ) interval when the jaw begins opening for the target vowel (V2 ), whereas peak MPT activation occurred around the temporal midpoint of V2 , when the jaw begins closing for C2 . EMG amplitude peaks differed in magnitude between "high" vowels, i.e., for which the tongue/jaw are high (e.g., in SEEK), and "low" vowels, i.e., for which the tongue/jaw are low (e.g., in SOCK). These novel findings suggest a key role for the LPT and MPT in the fine control of speech production. They imply that speech may impose major synergistic demands on the activities of the MPT and the LPT, and thereby provide insights into the possible interactions between speech activities and orofacial activities (e.g. mastication) and conditions (e.g. Temporomandibular Disorders) that involve the masticatory muscles.

Processing of linguistic and indexical information in adult cochlear implant users

Normal-hearing (NH) listeners simultaneously make use of both linguistic (speech content) and indexical (talker-specific) information in speech perception. For adult cochlear implant (CI) users, limitations in the talker-specific details conveyed by their devices may impact processing dependences between linguistic and indexical information. The current study examined the extent to which linguistic and indexical information are processed interdependently in adult CI users, using speeded phoneme and talker gender classification tasks. Higher-performing adult CI users (open-set word recognition >65% correct) reported the target vowel (phoneme classification) or target talker gender (gender classification). The non-target dimension varied by the number of talkers (phoneme classification) and the number of words (gender classification). Largely consistent with NH findings, adult CI users displayed asymmetric interference between linguistic and indexical dimensions. Phoneme classification was less accurate and slower with high talker variability. In contrast, gender classification was not affected by word variability. Processing dependencies also varied across individual CI users and related to auditory and cognitive-linguistic abilities. These preliminary findings suggest that adult CI users may make use of degraded linguistic and indexical information during speech processing. However, the extent to which they do so may depend on individual auditory and cognitive-linguistic factors.

The effectiveness of embodied prosodic training in L2 accentedness and vowel accuracy

This study explores the effects of embodied prosodic training on the production of non-native French front rounded vowels (i.e. /y, ø, œ/) and the overall pronunciation proficiency. Fifty-seven Catalan learners of French practiced pronunciation in one of two conditions: one group observed hand gestures embodying prosodic features of the sentences they were listening to, while the other group did not see any such gestures. The learning outcome was assessed in a pretest, posttest, and delayed posttest through a dialogue-reading task and a sentence imitation task in terms of accentedness, comprehensibility and fluency scores, and through formant analysis of participant-produced target vowels. The results showed that compared to non-embodied training, embodied prosodic training yielded continuous improvement in accentedness in both tasks and improved the F2 values of French front rounded vowels (more fronted). As for comprehensibility and fluency scores, both groups showed similar levels of significant improvement. This study highlights the interaction between prosodic and segmental features of speech by showing that training with embodied prosodic features benefitted accentedness and the production accuracy of non-native vowels.

Intelligibility of speech produced by sighted and blind adults.

PurposeIt is well known that speech uses both the auditory and visual modalities to convey information. In cases of congenital sensory deprivation, the feedback language learners have access to for mapping visible and invisible orofacial articulation is impoverished. Although the effects of blindness on the movements of the lips, jaw, and tongue have been documented in francophone adults, not much is known about their consequences for speech intelligibility. The objective of this study is to investigate the effects of congenital visual deprivation on vowel intelligibility in adult speakers of Canadian French.MethodTwenty adult listeners performed two perceptual identification tasks in which vowels produced by congenitally blind adults and sighted adults were used as stimuli. The vowels were presented in the auditory, visual, and audiovisual modalities (experiment 1) and at different signal-to-noise ratios in the audiovisual modality (experiment 2). Correct identification scores were calculated. Sequential information analyses were also conducted to assess the amount of information transmitted to the listeners along the three vowel features of height, place of articulation, and rounding.ResultsThe results showed that, although blind speakers did not differ from their sighted peers in the auditory modality, they had lower scores in the audiovisual and visual modalities. Some vowels produced by blind speakers are also less robust in noise than those produced by sighted speakers.ConclusionTogether, the results suggest that adult blind speakers have learned to adapt to their sensory loss so that they can successfully achieve intelligible vowel targets in non-noisy conditions but that they produce less intelligible speech in noisy conditions. Thus, the trade-off between visible (lips) and invisible (tongue) articulatory cues observed between vowels produced by blind and sighted speakers is not equivalent in terms of perceptual efficiency.

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.

Reflections of the French nasal vowel shift in orthography on Twitter

AbstractNon-standard orthography on social media provides a useful supplementary data source for sociophonetic research. Regarding an ongoing chain shift in Northern Metropolitan French nasal vowels, spellings reflecting shifted vowel targets are observed on Twitter. These non-standard spellings, e.g. avont [avɔ̃] for avant /avɑ̃/ ‘before’, provide insight into speakers’ awareness of this change and its lexical distribution. Tweets with shifted and standard spellings of 306 word forms containing the phonemes /ɛ̃/, /œ̃/, /ɑ̃/ and /ɔ̃/ were collected from an 870-million word Internet Archive corpus of French tweets from 2011–2017. Shifted spellings were found for all four vowels and 168 words. The shifted spelling rate is lower than that of comparable variables in English and is not conditioned by stress, grammatical category, frequency, or phonological context, which affect the distribution of shifted nasal vowels in speech. However, frequent words show more indications of intentional misspelling, such as repetition and capitalization of the target vowel, suggesting that some speakers are conscious of the variation and comment on it using salient words. The results also contribute to an ongoing debate about a possible merger between /ɛ̃/ and /œ̃/, supporting the hypothesis of an incomplete merger where /ɛ̃/ shifts towards [ɑ̃] but /œ̃/ does not.

Dynamic targets in second language vowel articulations

This study examines L1 English-L2 French vowel productions, with the goal of exploring whether representing vowel targets as dynamic rather than “steady-state” better predict L2 production patterns. It is hypothesized that learners will transfer L1 vowel dynamic information to produce L2 vowels if the two are perceived as “similar,” but it is unclear whether learners will transfer dynamic vowel information to “new” L2. As such, six L1 English-L2 French learners completed production tasks in English and French with the target vowels /i, u, e, o/ and /y, ø/ in real words. Participants were recorded using a stabilization headset attached to an ultrasound probe and microphone. F1 and F2 measurements and tongue contours were extracted at three timepoints throughout the vowel duration. Results shows that while learners produce L2 French vowels /i, e, u, o/ with a similar amount of formant and gestural movement to L1 vowels, they do not transfer midpoint F1-F2 values. Learners do produce new L2 vowels /y, ø/ with similar formant and gestural movements to English vowels. The results of this study indicate that learners transfer dynamic acoustic information and articulatory gestures from their L1 to produce L2 vowels, which has implications for the representation of vowels.

Talker and sentence variability attenuates speaking rate normalization in speech perception

Speech perception is shaped by acoustic context effects, where acoustic properties of earlier (context) sounds influence categorization of later (target) sounds. These context effects are sensitive to talker characteristics. When context sentences were spoken by a different talker on each trial, spectral contrast effect (SCE) magnitudes affecting categorization of the target vowel were smaller than when sentences were spoken by a single talker [Assgari and Stilp, J. Ascoust. Soc. Am. (2015)]. Here, perceptual consequences of talker variability were examined in Temporal Contrast Effects (TCEs; also termed rate normalization). Each trial presented a context sentence (spoken at a fast or slow rate) followed by a target word varying from “deer” to “tier.” Context sentences were the same stimuli from Assgari and Stilp (2015): one talker speaking the same sentence on each trial, one talker speaking a different sentence on each trial, and 200 talkers each speaking a different sentence on each trial. TCE magnitudes significantly decreased between One Talker/One Sentence and One Talker/200 Sentences, and again between One Talker/200 Sentences and 200 Talkers/200 Sentences. Conversely, in Assgari and Stilp, talker variability diminished SCEs but sentence variability for a single talker did not. These results suggest that variability in different acoustic domains restricts speech perception.

The effect of competitor rhythmic structure when recalling vowels in a complex listening environment

Research has shown that the rhythmic structure of speech is relevant to listening outcomes in complex environments. Several studies have shown that an intact, natural target rhythm facilitates listeners’ perception of auditory signals. However, less is known about the effect of competitor signal rhythmic structure on target recognition. The current study uses a synthetic vowel identification paradigm to investigate the influence of the rhythmic structure of to-be-ignored competing signals on listeners’ ability to identify speech information in a target signal. Listeners were tasked with identifying the last three vowels of target sequences of varying length presented alongside competing sequences consisting of either vowel-like harmonic tone complexes or similar vowels. The inter-onset-intervals in these sequences were manipulated to create conditions where the internal rhythm of the sequences was either isochronous or irregular. Competitor rhythm was found to be a significant factor for target recognition only with the vowel-sequence competitors. Isochronous target vowel recognition was better for vowel-sequence competitors with an irregular rhythm than with a regular (isochronous) rhythm. The results of this study highlight (1) the relevance of the rhythmic structure in selective listening tasks and (2) the importance of target and competitor similarity in determining the influence of competitor rhythm.

Orthography does not hinder non-native production learning in children

Children are known to be fast learners due to their neural plasticity. Learning a non-native language (L2) requires the mastering of new production patterns. In classroom settings, learners are not only exposed to the acoustic input, but also to the unfamiliar grapheme–phoneme correspondences of the L2 orthography. We tested how 9–10-year-old children, with Finnish as a native language (L1), respond to a two-day listen-and-repeat training paradigm, where they simultaneously hear acoustic stimuli and see orthographic cues. In the procedure, non-words containing the L2 vowel /ʉ/ were presented simultaneously with an orthographic cue showing <u>, guiding pronunciation towards the L1 vowel /u/ according to Finnish grapheme–phoneme correspondences. Earlier studies showed that Finnish adults rely on the orthographic cue over the acoustic one, leading them to produce /u/ instead of /ʉ/ when presented with the incongruent L1–L2 grapheme–phoneme correspondence (<u> – L1: /u/, L2: /ʉ/). Also, an earlier result from age-matched children receiving only acoustic input showed relatively fast pronunciation changes towards the target vowel. Our present results indicate clear and fast production learning of the non-native sound, and the misleading orthographic cue did not draw attention away from the target acoustic form. With orthographic cues, the participants learned to produce novel sounds faster than without them.

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.

The Merger of /e/ and /ɛ/ in Seoul Korean Tracing Speakers Born from the 1930s to the 1960s

It is well-known that the vowel /ɛ/ has already been merged into /e/ in Seoul Korean, but two questions still remain unanswered: when this sound change began and who led it. To answer these questions, we extracted speech data of 66 speakers born between the 1930s and the 1970s from The Speech Corpus of Reading-Style Standard Korean. In total, 1056 vowel tokens were selected from eight target words containing each vowel from each speaker, and the F1 and F2 values of each target vowel were manually measured. Results suggest that female speakers born before or in the 1940s initiated the vowel merger, which began to be transmitted and diffused into males’ speech approximately a generation (30 years) later. The results of the study hinted at the direction of the merger; the two vowels were first merged in the F2 space, followed by a further neutralization toward F1. The findings of the present study support the general tendency of female-led sound changes and advance further understanding of the merger of /e/ and /ɛ/ in Seoul Korean by answering the two unresolved questions.

Variation in back vowel fronting and diphthongization in Louisiana English

Fronting of /u o ʊ/ vowel classes is prominent in Southern American English (SAE). This study was focused on Louisiana, a southern state where not all SAE features have had a strong hold. Dynamic formant trajectories of the target vowels were analyzed because different vowel fronting mechanisms were proposed for SAE and mainstream American English (Koops, 2010), and because formant trajectories of back vowels are rarely examined (Stanley and Renwick, 2020). Thirteen White and five Black college-aged females produced 24 monosyllabic words with vowels of each class as a part of a larger study. In White speakers, mean normalized F2 values at midpoints of /u o ʊ/ were not different from each other or from the central vowel /ʌ/, used as a reference. In Black speakers, /ʊ/'s F2 was similar to /ʌ/, but /u o/'s F2 was lower than in /ʌ/. In all speakers, formant trajectories of /u o/ were back-gliding, while /ʊ/ was center-gliding. Trajectory lengths of /u o/ were longer in White than in Black speakers. These results suggest that /u/ fronting was mainstream-like (nucleus fronting and a backglide) and that /u o/ fronting was more advanced in White than in Black female speakers.

Recalling vowel sequences in completing backgrounds: Effects of rhythmic regularity and tempo

Previous studies have demonstrated that the rhythmic regularities embedded in naturally produced speech are essential for speech understanding in the presence of competing backgrounds. In the current study, the facilitative effect of rhythmic regularity was further investigated using a vowel-recall task. Listeners recalled the last three vowels from a sequence of 9 to 18 synthetic vowels presented at an average rate of 2 vowels/second along with a competing sequence of harmonic complexes. Through this task, the rhythmic regularity (isochronous or anisochronous) and tempo of the target and competitor sequences as well as the duration of exposure to target rhythmic context (i.e., the target sequence length) were independently manipulated without affecting the intelligibility of individual target vowels. Better recall performance was found for isochronous target sequences compared to anisochronous target sequences and with longer exposure to the rhythmic context prior to recall. The rhythmic regularity of the competing signal had no significant effect on recall performance; however, the tempo of the competing signal was significant with recall performance improving as the background tempo increased from 1 to 4 vowels/second. These effects of rhythm and tempo are consistent with theories of selective listening based on attentional entrainment.

Effectiveness of Mobile Assisted Pronunciation Training in the Acquisition of English Vowels, /o/ and /ɔ/

With the wide availability of mobile devices, efforts to accommodate these technological devices have been made in pronunciation training. This study aimed to investigate the effectiveness of mobile apps in improving the perception and production of the English vowels, /o/ and /ɔ/, which are difficult to discriminate and produce for Korean learners of English. The participants were 24 college freshmen enrolled in a general English course. They shadowed the model pronunciation from the application and corrected their production after instant feedback from the automatic speech recognition application. Their perception was evaluated in the preand post-tests, and the production was visually examined on the formant chart. The training was held for 5 minutes each day, for a month. The results showed that the training made positive effects on improving students’ perception of the target vowels. There was also some progress in their production although the improvement was not as noticeable as in perception. A discrepancy in the production was discovered between male and female participants with the latter performing better.

Developmental differences in perceptual anticipation underlie different sensitivities to coarticulatory dynamics.

Anticipatory coarticulation is an indispensable feature of speech dynamics contributing to spoken language fluency. Research has shown that children speak with greater degrees of vowel anticipatory coarticulation than adults - that is, greater vocalic influence on previous segments. The present study examined how developmental differences in anticipatory coarticulation transfer to the perceptual domain.Using a gating paradigm, we tested 29 seven-year-olds and 93 German adult listeners with sequences produced by child and adult speakers, hence corresponding to low versus high vocalic anticipatory coarticulation degrees. First, children predicted vowel targets less successfully than adults. Second, greater perceptual accuracy was found for low compared to highly coarticulated speech. We propose that variations in coarticulation degrees reflect perceptually important differences in information dynamics and that listeners are more sensitive to fast changes in information than to a large amount of vocalic information spread across long segmental spans.

How Do Speakers of a Language with a Transparent Orthographic System Perceive the L2 Vowels of a Language with an Opaque Orthographic System? An Analysis through a Battery of Behavioral Tests

Background: The present study aims to investigate the effect of the first language (L1) orthography on the perception of the second language (L2) vowel contrasts and whether orthographic effects occur at the sublexical level. Methods: Fourteen adult Greek learners of English participated in two AXB discrimination tests: one auditory and one orthography test. In the auditory test, participants listened to triads of auditory stimuli that targeted specific English vowel contrasts embedded in nonsense words and were asked to decide if the middle vowel was the same as the first or the third vowel by clicking on the corresponding labels. The orthography test followed the same procedure as the auditory test, but instead, the two labels contained grapheme representations of the target vowel contrasts. Results: All but one vowel contrast could be more accurately discriminated in the auditory than in the orthography test. The use of nonsense words in the elicitation task eradicated the possibility of a lexical effect of orthography on auditory processing, leaving space for the interpretation of this effect on a sublexical basis, primarily prelexical and secondarily postlexical. Conclusions: L2 auditory processing is subject to L1 orthography influence. Speakers of languages with transparent orthographies such as Greek may rely on the grapheme–phoneme correspondence to decode orthographic representations of sounds coming from languages with an opaque orthographic system such as English.

New Zealand English in Auckland

Abstract This study acoustically analyses the vowel space of adult New Zealand English speakers from a predominantly Pasifika suburb in Auckland (Papatoetoe). These speakers (n = 13) are compared to two equivalent groups from non-Pasifika Auckland suburbs, Mount Roskill (n = 14) and Titirangi (n = 6). All participants are New Zealand English speakers aged 16–25. There were equal numbers of male and female participants. For the acoustic analysis vowels with sentence stress were identified and extracted and formant values were calculated at the vowel target. This study looks at over 8000 monophthongs and 4000 diphthongs. The study found minimal differences between speakers from different suburbs, but all groups had notable differences from the traditional New Zealand English (NZE) vowel space. These differences align with previous comments regarding the vowels of Pasifika New Zealand English. The paper concludes by contemplating what these results say about Pasifika New Zealand English and New Zealand English in Auckland.

Using ultrasound tongue imaging to study covert contrasts in second-language learners’ acquisition of English vowels

ABSTRACT Research attempting to understand the intermediate stages of first-language acquisition and disordered speech has led to the discovery of covert contrast. A covert contrast is a statistically reliable difference between phonemes that is produced by a language learner, but in a way that cannot be heard readily by a listener of the target language. In the present study, we aimed to extend the investigation of covert contrasts to the domain of second-language acquisition. In particular, we used ultrasound tongue imaging to examine whether adult second-language learners of American English produced articulatory distinctions between the target vowels, in addition to producing acoustic differences. We collected speech recordings from 21 speakers (7 Korean speakers, 7 Spanish speakers, 7 English controls) while they produced words illustrating the relevant vowel contrasts in English: /i/-/ɪ/ and /ɛ/-/æ/. Results showed that approximately 36% of our second-language participants implemented various patterns of covert contrast in vowel articulation. Ultrasound measurements revealed that two participants made a covert distinction between two vowels that were perceptually neutralized. For one participant, the anterior part of the tongue was higher for /i/ than /ɪ/, and for the other, it was higher for /ɛ/ than /æ/. Overall, our findings highlight the importance of a learner-oriented approach in studying the acquisition of phonemic contrasts and suggest that ultrasound tongue imaging can be a promising tool to examine the articulatory details of vowel production in second-language learners.