• Speech Sciences
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• v.1
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• pp.201-211
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• 1997

Acoustically a naturally-spoken vowel is composed of five formants. However, the acoustic quality of a vowel is known to be mostly determined by $F_1\;and\;F_2$. The main purpose of this study was to examine how synthesized vowels with $F_1\;and\;F_2$ are perceived by Korean native speakers. In addion, we are interested in finding whether the synthesized vowels are perceived differently by standard Korean speakers and Kyungnam regional dialect speakers. In the experiment 9 Seoul standard Korean speakers and 9 Kyungnam dialect speakers heard 536 vowels synthesized in vowel space with $F_1\;by\;F_2$ and categorized them into one of 10 Korean vowels. The resultant vowel map showed that each Korean vowel occupies an unique area in the two-dimensional vowel space of $F_1\;by\;F_2$, and confirmed that $F_1\;and\;F_2$ play important roles in the perception of vowels. The results also showed that the Seoul speakers and the Kyungnam speakers perceive the synthesized vowels differently. For example, /e/ versus /$\varepsilon$/ contrast, /y/, and /$\phi$/ are perceived differently by the Seoul speakers, whereas they were perceptually confused by the Kyungnam speakers. These results might be due to the different vowel systems of the standard Korean and the Kyungnam regional dialect. While the latter uses a six-vowel system which has no /e/ vs /$/ contrast, /v/ vs /i/ contrast, /y/, and /$\phi$/, the former recognizes these as different vowels. This result suggests that the vowel system of differing dialect restricts the perception of the Korean vowels. Unexpectedly /i/ does not occupy any area in the vowel apace. This result suggests that /i/ cannot be synthesized without $F_3$.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.362-366
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• 1996

This paper is generally divided in 2 parts. One is the study on vowels about korean singer's lyric song in view of Daniel Jones' Cardinal Vowel. The other is acoustic study on vowels in my singing about korean lyric song. Analysis data are KBS concert video tape and CSL's. NSP file on my singing and Informants are famous singers i.e. 3 sopranos, 1 mezzo, 2 tenors, 1baritone, and me. Analysis aim is to find out Korean 8 vowels([equation omitted]) quality in singing. The methods of descrition are used in closed vowels, half closed vowels, half open vowels, open vowels and rounded vowels, unroundes vowels and formants. The study of the former is while watching the monitor screen to stop the scene that is to be analysixed. The study of the latter is to analysis the spectrogram converted by CSL's. SP file. Analysis results are an follows: Visual and auditory korean vowels quality in singing have the 3 tendency. One is the tendency of more rounded than is usual Korean vowels. Another is the tendency of centralized to center point in Cardinal Vowel and the other is the tendency of diversity in vowel quality. Acoustic analysis is studied by means of 4 formants. Fl and F2 show similiar step in spoken. In Fl there is the same formant values. This seems to vocal organization be perceived the singign situation. The width of F3 is the widest of all, so F3 may be the characteristics in singing. In conclude, the characteristics of vowels in Korean lyric songs are seems to have the tendencies of rounding, centralizing to center point in Cardinal Vowel, diversity in vowel quality and, F3'widest width in compared with usual Korean vowels.

• Phonetics and Speech Sciences
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• v.6 no.1
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• pp.39-45
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• 2014

This study investigates twenty four Korean females' production of English front vowels focusing on the distinction in /i/ vs /ɪ/ and /ɛ/ vs /${\ae}$/ and formant values of stressed and unstressed vowels compared with those of native English speakers. The Korean learners were asked to read a textbook passage which includes ten sentences including target vowels. The major results indicate that: (1) Korean learners have trouble producing a distinct version (tense and lax) of front vowels in the paragraph reading; (2) The vowel space of the stressed vowels in a paragraph is smaller than that of embedded sentences; and (3) The vowel quality of the unstressed vowels produced by the Korean learners is similar to that of the native English speakers. The findings from this study can be applied to the pronunciation teaching for the Korean learners of English vowels and realization of English stress.

• The Journal of the Korea Contents Association
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• v.13 no.9
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• pp.495-503
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• 2013

The purpose of this study was to investigate how Korean speakers produce English vowels. Twenty one Korean learners produced the vowels [i, ɪ, eɪ, ɛ, æ, ɑ, ʌ, ɔ, oʊ, ʊ, u] in bVt or pVt forms of real words. Acoustic measurements were conducted for the vowel formant frequencies (F1, F2) and duration. Results showed that Korean learners tended to produce the vowel duration longer than native English speakers. Also, the front vowels produced by Korean participants tended to be produced at the more frontal part of the tongue. In addition, Korean participants distinguished the tense and lax pairs not through quality(F1, F2) but through vowel duration. This is different from the native English speakers in that they differentiate tense and lax pairs by quality(F1, F2) as well as vowel duration. Based on these results, pedagogical implications are discussed.

• Phonetics and Speech Sciences
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• v.5 no.3
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• pp.31-38
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• 2013

This study investigated the influence of English vowel pronunciation training to English word-initial stop pronunciation. For that purpose, VOT values of English stops produced by twenty Korean English learners(five Youngnam dialect male speakers, five Youngnam dialect female speakers, five Kangwon dialect male speakers, and five Kangwon dialect female speakers) were measured using the Speech Analyzer and their post-training production was compared with their pre-training production. The result shows that post-training VOT values of voiced stops became closer to those of native English speakers in all four groups. Hence, it can be inferred that vowel pronunciation training is effective for correcting pronunciation of voiced vowels by analyzing the change of the quality of following vowels(especially low vowels) and the degree of giving stress.

• Speech Sciences
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• v.4 no.1
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• pp.19-34
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• 1998

The author collected and compared midsagittal, coronal, coronal oblique, and transversal images of Korean monophthongs /a, i, e, o, u, i, v/ produced by a healthy male speaker using 1.5 T MR, VISION. Area was measured by computer software after tracing the cross-section at different points along the tract. Results showed that the width of the oral and pharyngeal cavities varied compensatorily from each other on the midsagittal dimension. Formant frequency values estimated from the area functions of the seven vowels showed a strong correlation (r=0.978) with those analyzed from the spoken vowels. Moreover, almost all of 35 students who listened to the synthesized vowels from area data perceived the synthesized vowels as equivalent to the spoken ones. Movement of constriction points of vowel /u/ with wider lip opening sounded /i/ and led to slight changes in vowel quality. Jaw and tongue movement led to major volume variation with an anatomical limitation. Each comer vowel varied systematically from a somewhat constant volume of the average area. Thus, the author proposed that any simulation studies related to vocal tract area variation should reflect its constant volume. The results may be helpful to verify exact measurement of the vocal tract area through vowel synthesis and a simulation study before having any operation of the vocal tract.

• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.57-66
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• 2021

This study focuses on the issue of automatic severity classification of dysarthric speakers based on speech intelligibility. Speech intelligibility is a complex measure that is affected by the features of multiple speech dimensions. However, most previous studies are restricted to using features from a single speech dimension. To effectively capture the characteristics of the speech disorder, we extracted features of multiple speech dimensions: voice quality, prosody, and pronunciation. Voice quality consists of jitter, shimmer, Harmonic to Noise Ratio (HNR), number of voice breaks, and degree of voice breaks. Prosody includes speech rate (total duration, speech duration, speaking rate, articulation rate), pitch (F0 mean/std/min/max/med/25quartile/75 quartile), and rhythm (%V, deltas, Varcos, rPVIs, nPVIs). Pronunciation contains Percentage of Correct Phonemes (Percentage of Correct Consonants/Vowels/Total phonemes) and degree of vowel distortion (Vowel Space Area, Formant Centralized Ratio, Vowel Articulatory Index, F2-Ratio). Experiments were conducted using various feature combinations. The experimental results indicate that using features from all three speech dimensions gives the best result, with a 80.15 F1-score, compared to using features from just one or two speech dimensions. The result implies voice quality, prosody, and pronunciation features should all be considered in automatic severity classification of dysarthria.

• Speech Sciences
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• v.7 no.1
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• pp.109-141
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• 2000

Acoustic and aerodynamic characteristics of Cheju consonants were examined with the focus on the well-known three-way distinction among stops (i.e., lenis, fortis, aspirated) and the two-way distinction between sand s*. Acoustic parameters examined for the stops included VOT, relative stop burst energy, Fo at the vowel onset, H1-H2, and H1-F2 at the vowel onset. For the fricatives s and s*, acoustic parameters were fricative duration, Fo, centroid of the fricative noise, RMS energy of the frication, H1-H2 and Hl-F2 at the onset of the following vowel. In investigating aerodynamics, intraoral pressure and oral flow were included for the bilabial stops. Results indicate that, although Cheju and Korean are not mutually intelligible, acoustic and aerodynamic properties of Cheju consonants are very similar in every respect to those of the standard Korean. Among other findings there are three crucial points worth recapitulating. First, stops are systematically differentiated by the voice quality of the following vowel. Second, stops are also differentiated by aerodynamic mechanisms. The aspirated and fortis stops are similar in supralaryngeal articulation, but employ a different relation between intraoral pressure and flow. Finally, our study suggests that the fricative s is better categorized as 'lenis' than as 'aspirated' in terms of its phonetic realization.

• Phonetics and Speech Sciences
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• v.9 no.1
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• pp.49-53
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• 2017

Formant frequencies depend on the position of tongue, the shape of lips, and larynx. In the auditory system, the external ear canal is an open-end resonator, which can modify the voice characteristics. This study investigates the effect of the real ear on formant frequencies. Fifteen subjects ranging from 22 to 30 years of age participated in the study. This study employed three corner vowels: the low central vowel /a/, the high front vowel /i/, and the high back vowel /u/. For this study, the voice of a well-educated undergraduate who majored in speech-language pathology, was recorded with a high performance condenser microphone placed in the upper pinna and in the ear canal. Paired t-test showed that there were significant difference in the formant frequencies of F1, F2, F3, and F4 between the free field and the real ear. For /a/, all formant frequencies decreased significantly in the real ear. For /i/, F2 increased and F3 and F4 decreased. For /u/, F1 and F2 increased, but F3 and F4 decreased. It seems that these voice modifications in the real ear contribute to interpreting voice quality and understanding speech, timbre, and individual characteristics, which are influenced by the shape of the outer ear and external ear canal in such a way that formant frequencies become centralized in the vowel space.

• Proceedings of the KSPS conference
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• 1996.10a
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• pp.53-69
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• 1996

Much research has been done on the rues differentiating the three Korean stops in word initial position. This paper focuses on a more neglected area: the acoustic cues differentiating the medial tense and lax unaspirated stops. Eight adult Korean native speakers, four males and four females, pronounced sixteen minimal pairs containing the two series of medial stops with different preceding vowel qualities. The average duration of vowels before lax stops is 31 msec longer than before their tense counterparts (70 msec for lax vs 39 msec for tense). In addition, the average duration of the stop closure of tense stops is 135 msec longer than that of lax stops (69 msec for lax vs 204msec for tense). THESE DURATIONAL DIFFERENCES ARE 50 LARGE THAT THEY MAY BE PHONOLOGICALLY DETERMINED, NOT PHONETICALLY. Moreover, vowel duration varies with the speaker's sex. Female speakers have 5 msec shorter vowel duration before both stops. The quality of voicing, tense or lax, is also a cue to these two stop types, as it is in initial position, but the relative duration of the stops appears to be much more important cues. The duration of stops changes the stop perception while that of preceding vowel does not. The consequences of these results for the phonological description of Korean as well as the synthesis and automatic recognition of Korean will be discussed.