• Phonetics and Speech Sciences
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• v.15 no.4
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• pp.11-16
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• 2023

The present study examines how a cognitive attention affects Korean learners of English (L2) in perceiving the English stop voicing distinction (/d/-/t/). This study tested the effect of attentional distractor on primary and non-primary acoustic cues, focusing on the role of Voice Onset Time (VOT) and fundamental frequency (F0). Using the dual-task paradigm, 28 Korean adult learners of English participated in the stop identification task carried with (distractor) and without (no-distractor) arithmetic calculation. Results showed that when distracted, Korean learners' sensitivity to VOT decreased as priorly reported with native English speakers. Furthermore, as F0 is a primary cue for a L1 Korean stop laryngeal contrast, its role in L2 English voicing distinction was also affected by a distractor, without compensating for the reduced VOT sensitivity. These findings suggest that flexible use of multiple cues in L1 is not necessarily beneficial for L2 phonological processing when coping with a adverse listening condition.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.29-37
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• 2010

Previous studies have investigated a between-category relationship of multiple acoustic cues for a laryngeal contrast by examining the distributions of VOT, f0 and H1-H2. The current study examined within-category correlations between cues comprising stops by Korean- and English-speaking adults and children to understand how children master the internal structure of stop phonation types in two languages. Word-initial stops were collected from about 70 children and 15 adults speaking English and Korean, and were analyzed in terms of VOT, f0 and H1-H2 to compute correlation coefficients. Findings in adults' productions included a gender-differentiated cue-correlation pattern associated with H1-H2 in Korean tense stops and a trading relationship between f0 and VOT in Korean lax and aspirated stops and English voiced and voiceless stops. Children did not necessarily have adult-like cue-correlation patterns even in early-acquired categories, suggesting that the mastery of intra-category structure of phonation type might occur later than inter-category structure.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.31-41
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• 2012

Recent studies have shown that the stop system of Korean is undergoing a sound change in terms of the two acoustic parameters, voice onset time (VOT) and fundamental frequency (f0). Because of a VOT merger of a consonantal opposition and onset-f0 interaction, the relative importance of the two parameters has been changing in Korean where f0 is a primary cue and VOT is a secondary cue in distinguishing lax from aspirated stops in speech production as well as perception. In English, however, VOT is a primary cue and f0 is a secondary cue in contrasting voiced and voiceless stops. This study examines how Korean English learners use the two acoustic parameters of L1 in producing L2 English stops and whether the sound change of acoustic parameters in L1 affects L2 speech production. The data were collected from six adult Korean English learners. Results show that Korean English learners use not only VOT but also f0 to contrast L2 voiced and voiceless stops. However, unlike VOT variations among speakers, the magnitude effect of onset consonants on f0 in L2 English was steady and robust, indicating that f0 also plays an important role in contrasting the [voice] contrast in L2 English. The results suggest that the important role of f0 in contrasting lax and aspirated stops in L1 Korean is transferred to the contrast of voiced and voiceless stops in L2 English. The results imply that, for Korean English learners, f0 rather than VOT will play an important perceptual cue in contrasting voiced and voiceless stops in L2 English.

• Phonetics and Speech Sciences
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• v.14 no.3
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• pp.1-9
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• 2022

The current study examined English-speaking adult learners' production and perception of L2 Korean stops (/t/ or /t'/ or /t^h/) to investigate whether the two modalities are linked in utilizing voice onset time (VOT) and fundamental frequency (F0) for the L2 sound distinction and how the learners' L2 proficiency mediates the relationship. Twenty-two English-speaking learners of Korean living in Seoul participated in the word-reading task of producing stop-initial words and the identification task of labelling CV stimuli synthesized to vary VOT and F0. Using logistic mixed-effects regression models, we quantified group- and individual-level weights of the VOT and F0 cues in differentiating the tense-lax, lax-aspirated, and tense-aspirated stops in Korean. The results showed that the learners as a group relied on VOT more than F0 both in production and perception (except the tense-lax pair), reflecting the dominant role of VOT in their L1 stop distinction. Individual-level analyses further revealed that the learners' L2 proficiency was related to their use of F0 in L2 production and their use of VOT in L2 perception. With this effect of L2 proficiency controlled in the partial correlation tests, we found a significant correlation between production and perception in using VOT and F0 for the lax-aspirated stop contrast. However, the same correlation was absent for the other stop pairs. We discuss a contrast-specific role of acoustic cues to address the non-uniform patterns of the production-perception link in the L2 sound learning context.

• Phonetics and Speech Sciences
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• v.7 no.3
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• pp.3-11
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• 2015

This study compared English and Korean speakers with regard to the nasalization of the English stops /b, d, g, p, t, k/before a nasal within and across a word boundary. Nine English and thirty Korean speakers participated in the experiment. We used 37 speech items with different grammatical structures. Overall the English informants rarely nasalized the stops while the Korean informants generally greatly nasalized them though widely varying from no nasalization to almost complete nasalization. In general, voiced stops were more likely to be nasalized than voiceless stops. Also, the alveolar stops /d, t/tended to be nasalized the most, the bilabial stops /b, p/ the second most, and the velar stops /g, k/ the least. Besides, the closer the grammatical relationship between neighboring words, the more likely the stop nasalization occurred. In contrast, the Korean syllabification - the addition of the vowel /i/ to the final stops - worked against the stop nasalization. On the other hand, different stress (accent) or rhythm effects of the two languages are assumed to contribute to the significantly different nasalization between English and Korean speakers. The spectrum of stop nasalization obtained from this study can be used as an index to measure how close a certain Korean speaker's stop nasalization is to English speakers'.

• Phonetics and Speech Sciences
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• v.11 no.4
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• pp.63-70
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• 2019

This study investigated individual variability of L2 learners' categorical judgments of L2 stops by exploring English learners' perceptual processing of two acoustic cues (voice onset time [VOT] and f0) and working memory capacity as sources of variation. As prior research has reported that English speakers' greater use of the redundant cue f0 was responsible for gradient processing of native stops, we examined whether the same processing characteristics would be observed in L2 learners' perception of Korean stops (/t/-/t^h/). 22 English learners of L2 Korean with a range of L2 proficiency participated in a visual analogue scaling task and demonstrated variable manners of judging the L2 Korean stops: Some were more gradient than others in performing the task. Correlation analysis revealed that L2 learners' categorical responses were modestly related to individuals' utilizations of a primary cue for the stop contrast (VOT for L1 English stops and f0 for L2 Korean stops), and were also related to better working memory capacity. Together, the current experimental evidence demonstrates adult L2 learners' top-down processing of stop consonants where linguistic and cognitive resources are devoted to a process of determining abstract phonemic identity.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.33-40
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• 2017

This study aimed to examine how Korean-English bilinguals make use of VOT and F0 cues in perception and production of Korean (lenis vs. aspirated) and English (voiced vs. voiceless) stops. It was explored whether bilinguals with extensive experience living in the U.S. exhibit native-like or interactive patterns in the cue use for both languages. Participants produced monosyllabic word-initial stops within a carrier sentence in each language, and performed forced-choice identification tasks with synthesized stimuli varying in 7 VOT steps and 7 F0 steps with base tokens of /$t^han$/ for Korean and /$t{\ae}n$/ for English. Listeners were required to select either /tan/ or /$t^han$/ for Korean and either /$d{\ae}n$/ or /$t{\ae}n$/ for English. The results from binary logistic regression analyses for each listener indicated that all bilinguals placed greater weight on F0 than VOT when distinguishing between the Korean lenis and aspirated stops, and greater weight on VOT than F0 in distinguishing between the English voiced and voiceless stops. In terms of production, all participants showed remarkably overlapping ranges in the VOT dimension and separating ranges in the F0 dimension for the stop contrast of Korean, while forming overlapping ranges in the F0 dimension and separating ranges in the VOT dimension for the stop contrast of English. These results indicate that the bilinguals with extensive exposure to L2 manage the stop systems of the two languages independently, both in perception and production, employing the opposite cue use for stops in the two languages. It was also found that the absolute beta-coefficient values of the perceptual cues for Korean stops were generally smaller than those for English and those reported in a previous study as for later bilinguals, which may have resulted from Korean not being their dominant language.

• Phonetics and Speech Sciences
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• v.4 no.1
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• pp.13-20
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• 2012

A lax stop in Korean, one of the three laryngeal contrastive stops, has undergone a sound change in terms of its acoustic properties. Prior production studies described this recent lax stop as being differentiated from tense and aspirated stops primarily by fundamental frequencies (f0). And, the acoustic property of voice onset time (VOT) further separates tense stops from lax and aspirated stops. The current research explores how these two major acoustic parameters of f0 and VOT cue the three stop categories in Korean adult listeners' perception. Thirty-one native speakers of Korean participated in two experimental tasks: categorization judgment and within-category goodness ratings. Two sets of audio stimuli were prepared by synthesizing English and Korean male speakers' CV productions. The findings showed that while f0 cues listeners to lax stops as production patterns would predict, VOT were closely related to listeners' categorization and goodness ratings of lax stops. This suggests that accurate characterizations of the recent lax stop category need to be based on Korean speakers' perceptual behavior as well as production patterns.

• Phonetics and Speech Sciences
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• v.2 no.1
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• pp.41-50
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• 2010

The current study exploresacoustic variation induced by prosodic contexts in different speech styles,with a focus on motherese or child-directed speech (CDS). The patterns of variation in the acoustic expression of voicing contrast in English stops, and the role of prosodic factors in governing such variation are investigated in CDS. Prosody-induced acoustic strengthening reported from adult-directed speech (ADS)is examined in the speech data directed to infants at the one-word stage. The target consonants are collected from Utterance-initial and -medial positions, with or without focal accent. Overall, CDS shows that the prosodic prominence of constituents under focal accent conditions variesin the acoustic correlates of the stop laryngeal contrasts. The initial position is not found with enhanced acoustic values in the current study, which is similar to the finding from ADS (Choi, 2006 Cole et al, 2007). Individualized statistical results, however, indicate that the effect of accent on acoustic measures is not very robust, compared to the effect of accent in ADS. Enhanced distinctiveness under focal accent is observed from the limited subjects' acoustic measures in CDS. The results indicate dissimilar strategies to mark prosodic structures in different speech styles as well as the consistent prosodic effect across speech styles. The stylistic variation is discussed in relation to the listener under linguistic development in CDS.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.57-65
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• 2017

The current study explored how Korean-speaking children processed the multiple acoustic cues (VOT and f0) for the stop laryngeal contrast (/t'/, /t/, and /$t^h$/) and examined whether individual perceptual strategies could be related to a general cognitive ability performing executive functions (EF). 15 children (aged from 7 to 8) participated in the speech perception task identifying the three Korean laryngeal stops (3AFC) on listening to the auditory stimuli of C-/a/ with synthetically varying VOT and f0. They completed a series of EF tasks to measure working memory, inhibition, and cognitive shifting ability. The findings showed that children used the two cues in a highly correlated manner. While children utilized VOT consistently for the three laryngeal categories, their use of f0 was either reduced or enhanced depending on the phonetic categories. Importantly, the children's processing strategies of a f0 suppression for a tense-aspirated contrast were meaningfully associated with children's better cognitive abilities such as working memory, inhibition, and attentional shifting. As a preliminary experimental investigation, the current research demonstrated that listeners with inefficient processing strategies were poor at the EF skills, suggesting that cognitive skills might be responsible for developmental variations of processing sub-phonemic information for the linguistic contrast.