• 말소리와 음성과학
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• 제1권4호
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• pp.3-9
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• 2009

Acoustically English vowels are defined primarily by formant values. The measurements of the values have been usually made at a few time points of the vowel segment despite the fact that the majority of English vowel formants vary dynamically throughout the segment. This study attempts to collect acoustic data of the nine English vowels published by Hillenbrand et al. (1995) online and to examine the acoustic features of the English vowels for phoneticians and English teachers. The author used Praat to obtain the data systematically at six equidistant timepoints over the vowel segment. Obvious errors were corrected based on the spectrographic display of each vowel. Results show that the first two formant trajectories are important to separate the nine vowels within the front- or back-vowel groups. The third formant trajectories appear comparable except those of the high vowels. Second, the back vowels leave longer traces on the vowel space toward the locus of the following consonant /d/. Third, each vowel has inherent duration, pitch, and intensity patterns. The results match the findings of Yang (2009). From the results, the author concludes that dynamic spectral changes are important in specifying acoustic characteristics of English vowels. Further studies on the application of the vowel trajectories to English pronunciation lessons or on perceptual experiment of synthesized vowels are desirable.

• 말소리와 음성과학
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• 제5권2호
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• pp.81-90
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• 2013

The purposes of this study are to: (1) Compare the vowel production of English front vowels produced by Korean speakers using regional dialects and; (2) Investigate and compare the effectiveness of pronunciation training for each regional dialect group. To test these objectives, the English front vowels produced by five Youngnam dialect male speakers, five Youngnam dialect female speakers, five Kangwon dialect male speakers, and five Kangwon dialect female speakers were scrutinized. These dialect groups' vowel formants and length of English front vowels were evaluated, and the post-pronunciation training values were compared with those of pre-training values. The results indicate that pronunciation training is more effective for Youngnam dialect speakers, whilst both dialect groups have more success mastering the pronunciation of /${\varepsilon}$/ over /${\ae}$/.

• 말소리와 음성과학
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• 제9권2호
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• pp.1-7
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• 2017

The purpose of this study is to investigate the relations between phonetic differences among Korean learners' production of English front vowels, pronunciation intelligibility and speaking proficiency test score. To do so, thirty Korean university students were asked (1) to read English text book paragraphs and (2) describe a picture. Two English native raters and one Korean rater evaluated Korean subjects' English pronunciation intelligibility and speaking. In addition, subjects' English vowel productions were acoustically analyzed(F0, F1, F2, vowel duration, intensity). The results of the study show that the vowel quality and pitch of the unstressed vowels and lax vowel are related to the pronunciation intelligibility. In addition, the scores of pronunciation intelligibility and speaking are highly related.

• 말소리와 음성과학
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• 제5권4호
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• pp.129-136
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• 2013

This study investigated how acoustic characteristics (i.e., duration, F1, F2) of English high front vowels /i, ɪ/ are modulated by boundary- and prominence-induced strengthening in native vs. non-native (Korean) speech production. The study also examined how the durational difference in vowels due to the voicing of a following consonant (i.e., voiced vs. voiceless) is modified by prosodic strengthening in two different (native vs. non-native) speaker groups. Five native speakers of Canadian English and eight Korean learners of English (intermediate-advanced level) produced 8 minimal pairs with the CVC sequence (e.g., 'beat'-'bit') in varying prosodic contexts. Native speakers distinguished the two vowels in terms of duration, F1, and F2, whereas non-native speakers only showed durational differences. The two groups were similar in that they maximally distinguished the two vowels when the vowels were accented (F2, duration), while neither group showed boundary-induced strengthening in any of the three measurements. The durational differences due to the voicing of the following consonant were also maximized when accented. The results are discussed further in terms of phonetics-prosody interface in L2 production.

• 말소리와 음성과학
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• 제6권4호
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• pp.17-26
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• 2014

The present study examined epenthetic vowels produced by Korean learners of English in read sentences, in terms of acoustic measures and extra-phonological factors. The results demonstrated three main findings. First, epenthetic vowels had relatively high F1 values and a wide range of F2 values. Most of the epenthetic vowels were inserted near Korean high central vowels, but some vowels were inserted near front vowels due to co-articulation with surrounding vowels. Second, vowel epenthesis was affected by the context. The results showed that the epenthesis was frequently seen with word junctions between obstruents (e.g., stops-fricatives). Third, Korean learners were not affected by English background and were very weakly affected by orthography. English experience, which is one of the extra-phonological factors, was not related to epenthesis production. However, orthography, the other extra-phonological factor, very weakly affected the amount of epenthesis production. Nine percent of all epenthesis production was affected by the English past-tense suffix '-ed'; approximately 70% of the participants were affected by this suffix. The findings of the present study contributed to understanding vowel epenthesis. First, the study revealed that the epenthetic vowels produced by Korean learners of English were close to the high central vowel, supporting previous studies that the epenthetic vowel is quite close to the shortest vowel. Second, the study examined the various phonetic environments of epenthetic vowels, revealing that vowel epenthesis occurred more frequently in a certain phonetic circumstance.

• 말소리와 음성과학
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• 제6권4호
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• pp.91-99
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• 2014

Speaking styles tend to have an influence on spectral characteristics of produced speech. There are not many studies on the spectral characteristics of speech because of complicated processing of too much spectral data. The purpose of this study was to examine spectral characteristics and formant bandwidths of English vowels produced by nine American males with different speaking styles: clear or conversational styles; high- or low-pitched voices. Praat was used to collect pitch-corrected long-term averaged spectra and bandwidths of the first two formants of eleven vowels in the speaking styles. Results showed that the spectral characteristics of the vowels varied systematically according to the speaking styles. The clear speech showed higher spectral energy of the vowels than that of the conversational speech while the high-pitched voice did the same over the low-pitched voice. In addition, front and back vowel groups showed different spectral characteristics. Secondly, there was no statistically significant difference between B1 and B2 in the speaking styles. B1 was generally lower than B2 when reflecting the source spectrum and radiation effect. However, there was a statistically significant difference in B2 between the front and back vowel groups. The author concluded that spectral characteristics reflect speaking styles systematically while bandwidths measured at a few formant frequency points do not reveal style differences properly. Further studies would be desirable to examine how people would evaluate different sets of synthetic vowels with spectral characteristics or with bandwidths modified.

• 말소리와 음성과학
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• 제3권4호
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• pp.13-21
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• 2011

The present study investigated the effects of two different sources of prosodic strengthening, i.e., boundary and accent, in the articulation of English high front vowels, /i/ and /I/. The vowels were investigated in vowel-initial ('eat' vs. 'it'), /h/-initial ('heat' vs. 'hit') and /p/-initial words ('Pete' vs. 'pit'), which were placed in varying prosodic conditions. Using Electromagnetic Articulograph (EMA), the tongue dorsum positions in the x and y dimensions, the lip opening and the jaw opening (lowering) were measured. With respect to the boundary-induced strengthening, results showed that /i/ and /I/ in vowel-initial words ('eat' - 'it') are produced with a higher tongue position in the domain-intial than domain-medial positions. The fact that the vowels only in the vowel-initial condition showed the domain-intial strengthening (DIS) effect suggests that the DIS effect is localized mainly to the initial position (the locality account). As for the accent-induced strengthening, vowels were produced with a more fronted tongue position and larger lip opening in accented than unaccented positions. This suggests that the presence of accent increases overall sonority of the vowels in various prosodic contexts, and enhances primarily the frontedness of the front high vowels. Taken together, the results indicate that the two types of prosodic strengthening are articulatorily realized differently, supporting the view that they are encoded separately in the speech planning process. The present study also showed the distinction between the two high front vowels in the tongue position (in both the frontedness and the height dimensions), while the jaw did not seem to contribute to the distinction robustly, suggesting that the tongue contributes more in distinguishing the two vowels than the jaw does.

• 말소리와 음성과학
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• 제4권1호
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• pp.21-28
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• 2012

Many previous studies reported acoustic parameters of English vowels produced by a clear speaking style. In everyday usage, we actually produce speech sounds with various speaking styles. Different styles may yield different acoustic measurements. This study attempts to examine pitch and formant trajectories of eleven English vowels produced by nine American males in order to understand acoustic variations depending on clear and conversational speaking styles. The author used Praat to obtain trajectories systematically at seven equidistant time points over the vowel segment while checking measurement validity. Results showed that pitch trajectories indicated distinct patterns depending on four speaking styles. Generally, higher pitch values were observed in the higher vowels and the pitch was higher in the clear speaking styles than that in the conversational styles. The same trend was observed in the three formant trajectories of front vowels and the first formant trajectories of back vowels. The second and third trajectories of back vowels revealed an opposite or inconsistent trend, which might be attributable to the coarticulation of the following consonant or lip rounding gestures. The author made a tentative conclusion that people tend to produce vowels to enhance pitch and formant differences to transmit their information clearly. Further perceptual studies on synthesized vowels with varying pitch and formant values are desirable to address the conclusion.

• 음성과학
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• 제11권4호
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• pp.199-206
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• 2004

This paper attempts to provide a substantial explanation of different prosodic implementations on segments in English and Spanish, arguing that the phonetic modification invoked by prosody may effectively reflect phonological structure. In English, a high front vowel in accented syllables is acoustically realized as higher F1 and F2 frequencies than in unaccented syllables, due to its more peripheral and sonorous articulation (Harrington et al. 1999). In this paper, an acoustic experiment was conducted to see if such a manner of segmental modification invoked by prosody in English extends to other languages such as Spanish. Results show that relatively more prominent syllables entail higher F1 values as a result of their more sonorous articulation in Spanish, but either front or back vowel does not show a higher F2 or a lower F2 frequency. This is interpreted as an indication that a prosodically prominent syllable entails its vocalic enhancement in both horizontal and vertical dimensions of articulation in English. In Spanish, however, only the vertical dimensional articulation is maximized, resulting in a higher F1. I suggest that this difference may be attributed to the different phonological structures of vowels in English and Spanish, and that sonority expansion alone would be sufficient in the articulation of prosodic prominence as long as the phonological distinction of vowels is well retained.

• 음성과학
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• 제7권1호
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• pp.187-201
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• 2000

This study was done to investigate the English vowels in relation to the foreign accent. In this study, I also tried to find out the foreign accent of the English diphthong /o/ and front low vowel /${\ae}$/ when Koreans speak English. The reason why I chose these vowels is that these vowels, /o/ and /${\ae}$/, are difficult for Koreans to discern and pronounce. Koreans show a foreign accent in their pronunciation. In order to find out the reason for a Korean foreign accent, experiments were carried out with the help of acoustic instruments. According to the results of the experiment, Koreans showed a foreign accent in their English pronunciation of vowels in relation to their utterance positions. Americans showed a final lengthening effect but Koreans showed a final shortening effect. This means that Koreans showed a foreign accent in the final stressed syllable of a sentence. In addition to this, the duration of two English vowels, /o/ and /${\ae}$/, showed considerably different features between Koreans and Americans. In fact, in the pronunciation of the diphthong /o/, the tongue moves from one position to another. The two articulations of a diphthong can be described as the nucleus plus a glide. However, most Koreans have no idea of this phenomenon and pronounce the diphthongs like two separate monophthongs. This causes a great difference in the lengths of English diphthong /o/ between Koreans and Americans.