• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.9-17
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• 2021

Voice onset time (VOT) is known to be a primary acoustic cue that differentiates voiced from voiceless stops in the world's languages. While much attention has been given to the sound change of Korean stops, little attention has been given to that of English stops. This study examines VOT of stop consonants as produced by English speakers in comparison to Korean speakers to see whether there is any VOT change for English stops and how the effects of stop, place, gender, and individual on VOT differ cross-linguistically. A total of 24 native speakers (11 Americans and 13 Koreans) participated in this experiment. The results showed that, for Korean, the VOT merger of lax and aspirated stops was replicated, and, for English, voiced stops became initially devoiced and voiceless stops became heavily aspirated. English voiceless stops became longer in VOT than Korean counterparts. The results suggest that, similar to Korean stops, English stops may also undergo a sound change. Since it is the first study to be revealed, more convincing evidence is necessary.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.25-32
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• 2017

Besides their effect on the f0 contour of the following vowel, Korean stops are undergoing a sound change in which a partial or complete consonantal merger on voice onset time (VOT) is taking place between aspirated and lax stops. Many previous studies on sound change have mainly focused on group-normative effects, that is, effects that are representative of the population as a whole. Few systematic quantitative studies of change in adult individuals have been carried out. The current study examines whether the sound change holds for individual speakers. It focuses on inter-speaker and intra-speaker variability on sound change in contemporary Korean. Speech data were collected for thirteen Seoul Korean speakers studying abroad in America. In order to minimize the possible effects of speech production, socio-phonetic factors such as age, gender, dialect, speech rate, and L2 exposure period were controlled when recruiting participants. The results showed that, for nine out of thirteen speakers, the consonantal merger is taking place between the aspirated and lax stop in terms of VOT. There were also intra-speaker variations on the merger in three aspects: First, is the consonantal (VOT) merger between the two stops is in progress or not? Second, are VOTs for aspirated stops getting shorter or not (i.e., the aspirated-shortening process)? Third, are VOTs for lax stops getting longer or not (i.e., the lax-lengthening process)? The results of remarkable inter-speaker and intra-speaker variability indicate a synchronous speech sound change of the stop system in contemporary Korean. Some speakers are early adopters or active propagators of sound change whereas others are not. Further study is necessary to see whether the inter-speaker differences exceed intra-speaker differences in sound change.

• Phonetics and Speech Sciences
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• v.10 no.4
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• pp.91-99
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• 2018

Korean stops are currently undergoing a tonogenetic sound change, as found in the Seoul dialect in which a merged VOT of aspirated and lax stops induces F0 to be the primary cue for distinguishing the two stops and the lax stops have lower F0 than the aspirated stops. In tonal languages, low tone is produced with a breathy voice. This study investigated whether there are changes in voice quality with respect to the tonogenetic sound change of Korean stops. Two age groups speaking the Seoul dialect participated in this study: five females and six males born in the 1940s and 1950s and nine females and eight males born in the 1980s and 1990s. This study replicated previous findings of VOT and F0 and further examined H1-H2, H1-A1, and H1-A2 to see how they correlate with the sound change. In the older and younger generations, H1-H2, H1-A1, and H1-A2 were significantly lower after the tense stops than after the aspirated and lax stops, but they were not significantly different after the aspirated and lax stops. However, the younger females exhibited some different results for H1-H2 and H1-A2 than the older generation. In the younger females, the H1-H2 mean was higher after the aspirated stops than it was after the lax stops at the vowel onset, and the H1-H2 difference increased at the vowel midpoint. Although there was an inter-speaker variation in the results of H1-H2 and H1-A1, analyses of individual speakers showed that the H1-H2 and H1-A1 were higher after the lax stops than after the aspirated stops in the younger female speakers. These results indicate that lax stops tend to be breathier than aspirated stops in the younger female speakers. They also indicate that changes in voice quality are on Korean stops with tonal sound change, but are still developing.

• Phonetics and Speech Sciences
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• v.11 no.4
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• pp.35-43
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• 2019

This study examines the voice onset times (VOTs) of Korean stops produced by Korean learners of English with high language proficiency and long L2 exposure (i.e., Korean-English bilinguals) to assess whether the VOTs of their lax and aspirated stops are merging and, if so, which types of stops are being changed. Thirteen Korean speakers (six female and seven male) who had studied in the USA for more than three to ten years participated. The results show that the speakers in this study with long L2 exposure are participating in the VOT merger, in which VOTs for aspirated stops are reduced while those for lax stops are increased. In other words, change in VOT affects not only aspirated stops but also lax stops. The results indicate that L1 phonetic drift may not be primarily affected by the amount of L2 exposure, and language contact may not be the primary factor triggering a sound change in the Korean stop system. Further study is necessary focusing on the phonetic shift of the "lax" category because it may play a pivotal role in a tonogenetic-like sound change in present-day Korean.

• Phonetics and Speech Sciences
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• v.13 no.3
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• pp.39-51
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• 2021

Based on spontaneous speech data collected in 2020, this study examined the production and perception of Korean lenis, aspirated, and fortis stops. Unlike the controlled experiments of previous studies, lenis and aspirated stops of males in their 30s were not distinguished by voice onset time (VOT) in spontaneous speech. Perceptual experiments were conducted on young females, the leaders of language change. F0 was found to serve as the primary cue for the perception of lenis stops, and then VOT distinguished the aspirated and fortis stops. The fact that the sounds were always perceived as lenis stops when F0 was low, irrespective of whether VOT was short or long, showed that F0 plays an absolute role in the perception of lenis stops. However, in some cases the aspirated and lenis stops were distinguished only by VOT, which does not happen in production. In terms of sound change, disagreement between production and perception systems occurs when sound change is in progress. In particular, when production change precedes perception change, it indicates that the sound change is in its latter stages. Young females still maintain the previous system in perception because the distinction of lenis and aspirated stops by VOT was valid in their parents' generation. In other words, VOT is still used for perception to communicate with other groups.

• 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.9 no.3
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• pp.41-47
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• 2017

The purpose of this study is to examine how speakers use VOT and f0 to distinguish tense, lax, and aspirated stops in isolated sentence reading and paragraph readings. To do so, a total of 20 males between the ages of 20-25 years old were asked to read (1) isolated sentences, (2) information-oriented text and (3) emotional expressive texts in which the stop pronunciation's VOT value and f0 were measured thereafter. The main results are as follows. In the isolate sentence reading, lax stops, and aspirated stops were distinguished by both VOT and f0, but for the Korean men that read reading texts, VOT is not a cue to distinguish between lax and aspirated stops. In general, the VOT differences between lax stops and aspirated stops were smaller for information-oriented texts and emotional expressive texts than that of the isolate sentence reading. In the paragraph reading that induces a natural utterance, the f0 dependence is greater for the distinction between lax and aspirated stops.

• Phonetics and Speech Sciences
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• v.12 no.4
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• pp.9-17
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• 2020

Changes in the first language (L1) sound system as a result of acquiring a second language (L2) (i.e., phonetic drift) have received considerable attention from a variety of speakers, settings, and environments. Less attention has been given to phonetic drift in adult speakers' L2 learning as their length of residence in America (LOR) increases. This study examines the effects of LOR on voice onset time (VOT) in L1 Korean stops. Three different groups of Korean adult learners of L2 English were compared to assess how malleable their L1 representations are in terms of LOR and whether there is any relationship between L1 change and L2 acquisition. The results showed that the effect of LOR was linguistically unimportant in the production of Korean stops. However, VOT merger as evidence of sound change in Korean stops were robust in the speech production of most of the female speakers across the groups. The results suggest that L2 English may not be the primary cause of L1 sound change. For generalizability, further study is necessary to see whether other acoustic cues show a similar pattern.

• 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.3
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• pp.3-10
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• 2010

The proposal that a sound change is occurring in Korean stops was evidenced in this study through identification experiments on Korean stops. Perceptual weight of acoustic correlates to Korean stop manner contrast [VOT (Voice Onset Time), H1-H2 (amplitude difference between the first and second harmonics), and F0 (Fundamental frequency)] was examined with re-synthesized /$t^ha$/, /ta/, and /$t^*a$/ syllables for younger and older Seoul speakers of Korean. For the identification of the aspirated and lenis stops, F0 cue weight relative to VOT was greater for the younger listeners than the older listeners. For H1-H2 cue weight, the two listener groups were more or less the same. These findings were parallel to the production differences found in the earlier work of the author. Combined with production differences, these perception differences between younger and older generations of Seoul speakers suggested that there are generational differences in the phonetic targets of Korean aspirated and lenis stops and such differences are realized in the perception of the stops.