The aim of this dissertation is to investigate acoustic properties and perceptual cues of Korean word-initial obstruents. In order to conduct overall researches of whole Korean consonants that have two- and three-way contrasts of phonation types, the ...
The aim of this dissertation is to investigate acoustic properties and perceptual cues of Korean word-initial obstruents. In order to conduct overall researches of whole Korean consonants that have two- and three-way contrasts of phonation types, the present study analyzes whole Korean obstruents-stops, affricates, fricatives- with large scale of data through consistent methods. Because almost every previous studies of Korean obstruents have conducted only production experiments, this study investigates Korean obstruents with perceptual cues through perceptual experiment as well as acoustic properties through production experiment. Also, the present study deals with not only Seoul dialect but also Daegu dialect that has lexical tonal contrasts.
In the production experiment, 83 speakers in Seoul and Daegu dialect recorded 56 bi-syllable words that posit obstruents in word-initial position. I considered balances in the point of articulation, manner of articulation, phonation types and tone types(only Daegu dialect). This study examines voice onset time(VOT) in stops, duration of frication and aspiration in affricates and fricatives, and fundamental frequency(F0) as acoustic properties of obstruents. The results show that VOT of stops and duration of affricates that have three-way contrasts are in order of ？fortis<lenis<aspirated？ in both Seoul and Daegu dialect. Seoul and Daegu dialect are different in duration of lenis. In stops of Seoul dialect, lenis and aspirated. which have no significant difference aren't differentiated by VOT. However, VOT of lenis in Daegu lies between VOT of fortis and aspirated. Next, F0 of stops and affricates show a ？lenis<fortis<aspirated？ ordering. In the case of Seoul dialect, the F0 in lenis is relatively very low compared to other categories so that the lenis and other categories are distinguished clearly by F0. In Daegu dialect with lexical tonal contrasts, however, tone types as well as phonation types have significant difference of F0, even they have a major function in lexical tonal contrasts. Fricatives in two-way contrasts appear different aspects with stops and affticates in three-way contrasts. Duration of frication shows ？lenis<fortis？ ordering, while duration of aspiration shows ？fortis<lenis？ ordering. Although aspiration of fricatives in Daegu dialect has some overlapping parts between lenis and fortis, there is mostly clear line of division between two-way contrasts of fricatives both Seoul and Daegu dialect. In case of F0, there are no contrasts between lenis and fortis in fricatives.
In the perception experiment, the stimuli were made by manipulating the three lenis obstruents([tal] ？moon？, [ʨam] ？sleep？, and [sal] ？flesh？) by a female speaker of Seoul dialect. They were made in such a way that VOT in stops and duration of frication and aspiration respectively in affricates and fricatives were shortened or lengthened at 10ms intervals, and F0 were heightened or lowered at 1 semitone(ST) intervals. 103 subjects(51 in Seoul and 52 in Daegu dialect) participated in perception test. The results show that Seoul and Daegu dialect speakers perceive stops and affricates distinctively in three-way contrasts through interaction of duration for obstruents and F0. In perception of stops, all subjects perceive the stimuli with short VOT and high F0 as fortis, relatively long VOT and low F0 as lenis, and relatively long VOT and high F0 as aspirated. Seoul dialect speakers perceive the low F0 regardless VOT as lenis. Then, they perceive the aspirated with high F0 according to VOT as fortis. On the other hand, VOT functions as major perceptual cue in perception of fortis in Daegu dialect. Daegu dialect speakers perceive the short VOT regardless F0 as fortis. Then, they perceive as lenis and aspirated with relatively long VOT according to height of F0. In perception of affricates, however, all subjects perceive low F0 as lenis, the stimuli with short duration of affricate and high F0 as fortis, and the relatively long duration of affricate and high F0 as aspirated. Even though Daegu dialects speakers used cue of duration relatively, there is a little difference between dialects. It seems that other acoustic properties in frication phase affect perception of lenis and fortis in affricates. In the case of fricatives, only duration of aspiration functions as perceptual cue in the contrast of two categories in fricatives. That is, stops and affricates that have three-way contrast use interaction between duration of obstruent and F0 as perceptual cues, while fricatives that have two-way contrast use only duration of aspiration as a distinctive perceptual cue. In Daegu dialect, duration of obstruent conducts more important function in contrast of phonation types relative to Seoul dialect. It seems that F0 in Daegu dialect functions lexical tonal contrast as well as phonation type contrasts. While Seoul dialect show relatively big difference in F0 between lenis and other categories, Daegu dialect seems to be having relatively small differences among phonation types in order to conserve lexical tonal contrasts.
On Pulling together the results from the production and perception experiments ed here, and previous studies of phonation types in other languages, this study investigates phonation type contrasts in Korean obstruents. In addition, as one of the way for applying the results in this study, this study considers the way that can have implications in Korean education as foreign language. Korean has typologically unusual contrasts in obstruents. So when foreigners learn Korean, most difficult aspect in pronunciation is to distinguish contrasts of phonation types in obstruents. Chinese that has two-way contrasts in aspiration and English that has two-way contrast in voicing distinguish phonation types with VOT. So, while Chinese and English Korean Learners have distinction in fortis vs. other categories focusing on VOT, they cannot distinguish well between lenis and aspirated with F0. On the other hand, though Japanese has two-way contrasts in voicing like English, voiced vs. voiceless stops do not distinguish clearly by VOT. Because Japanese voiceless stops has intermediate degree of VOT, voiced vs. voiceless stop have a tendency to focus on F0 in order to distinguish phonation types. So, while Japanese Korean Learners have distinction in lenis vs. other categories focusing on F0, they cannot distinguish well between fortis and aspirated with VOT. Thus, Korean education for Chinese and English Korean learners should focus on F0 and for Japanese Korean learners on VOT. Differences of F0 between lenis and fortis, between lenis and aspiration are 4.1ST, 5.4ST respectively. So such a difference could be applied in Korean education for Chinese and English Korean Learners. AS Korean education for Japanese Korean learners should focus on VOT, difference of VOT between fortis and other categories could be applied. At this, because there is no significant VOT difference between lenis and aspirated, the education of distinction between lenis and aspirated through VOT is unnecessary.
This dissertation has significances as follows: This study conducts systematic research by analyzing whole Korean obstruents that have distinctions on phonation types. And this study investigates perceptual aspects as well as production aspects. In addition, this study deals with not only Seoul dialect but also Daegu dialect that have not gone far enough. As targeted Korean regional dialect with lexical tonal contrast, this study investigates not only difference of dialects, but also relationship of lexical tonal contrasts and phonation type contrasts. Also, because the three-way contrasts in Korean obstruents are unusual type typologically, it is no wonder that Korean learners have difficulty learning to distinguish that contrast. Moreover, due to hold a key post in Korean consonant system, contrasts of phonation types in Korean obstruents attract the notice of speech pathology and speech engineering. Therefore, the results of this thesis would be meaningful in providing foundation data in diverse application fields.
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