The purpose of this work is to examine the voice onset times (VOTs) of the three types of plosives from the Seoul Corpus male speakers in their twenties. In addition, the factors known to affect VOTs were analyzed, including the place and manner of articulation, speakers, location in words, type of following vowels and speech rates calculated from the three consecutive words. Much of the findings agreed with those from earlier studies on Korean and other languages and new discoveries were made.

This study investigated the patterns of coda deletion in spontaneous Seoul Korean speech. More specifically, the current study focused on three factors in promoting coda deletion, namely, word position, consonant type, and morpheme type. The results revealed that, first, coda deletion frequently occurred when affixes were attached to the ends of words, rather than in affixes in word-internal positions or in roots. Second, alveolar consonants [n] and [l] in the coda positions of high-frequency affixes [nɨn] and [lɨl] were most likely to be deleted. Additionally, regarding affix reduction in the word-final position, all subjects seemed to depend on this articulatory strategy to a similar degree. In sum, the current study found that affixes without primary semantic content in spontaneous speech tend to undergo the process of reduction, favoring the occurrence of specific pronunciation variants.

This study aims to examine whether the fundamental frequency (F0) varies depending on languages or distinguishes between L1 (first language) and L2 (second language) speech and whether the type of materials which vary in control of consonant voicing affects the use of F0-especially, mean F0. For this purpose, we compared productions of two languages produced by Korean L2 learners of English to those of Korean-English bilingual speakers. Twelve Korean L2 speakers of English and twelve Korean-English bilingual speakers participated in this study. The subjects read aloud 22 declarative sentences-balanced and unbalanced-once in English and once in Korean. Mean F0 of Korean was higher than that of English for both speaker groups, and the difference in the value of mean F0 between the Korean and English sentences was different depending on the type of materials that the participants read. With regard to F0 range, the L2 speakers had a larger F0 range in English than in Korean; however, the effect of language on F0 range was not statistically significant for the bilingual speakers. These results indicate that language-specific properties may affect the use of F0, in particular, mean F0.

The present study tested if individual speakers showing great sound change in segments (i.e., vowels and fricatives) also had innovative changing patterns in suprasegmental properties (i.e., lexical pitch accents) in Kyungsang Korean. The acoustic analysis at a group level first confirmed the presence of group level differences in distinguishing /ɨ-ʌ/ and /s-s'/ both of which had different phonemic distinction from Seoul Korean. Younger speakers had more innovative segmental change than older speakers, and even within the younger generation, female speakers produced more innovative phonetic variants than male speakers. Regarding the individual observation within the younger group, the younger speakers with large acoustic distinction in vowels and fricatives also showed acoustically less distinct accent patterns, indicating the innovative sound change pattern consistent across segment and suprasegmental properties. The group and individual observations suggested that linguistic innovators introduced new phonetic variants with consistent degree of changing pattern between segment and suprasegmental properties.

The purpose of the current study was to examine the acquisition of the second language prosody by Korean learners of English. Specifically, this study investigated Korean learners' patterns of prosodic phrasing and their use of edge tones (i.e., phrase accents and boundary tones) in English, and then compared the patterns with those of native English speakers. Eight Korean learners and 8 native speakers of English read 5 different English passages. Both groups' patterns of tones and prosodic phrasing were analyzed using the Mainstream American English Tones and Break Indices (MAE_ToBI) transcription conventions. The results indicated that the Korean learners chunked their speech into prosodic phrases more frequently than the native speakers did. This frequent prosodic phrasing pattern was especially noticeable in sentence-internal prosodic phrases, often where there was no punctuation mark. Tonal analyses revealed that the Korean learners put significantly more High phrase accents (H-) on their sentence-internal intermediate phrase boundaries than the native speakers of English. In addition, compared with the native speakers, the Korean learners used significantly more High boundary tones (both H-H% and L-H%) for the sentence-internal intonational phrases, while they used similar proportion of High boundary tones for the sentence-final intonational phrases. Overall, the results suggested that Korean learners of English successfully acquired the meanings and functions of prosodic phrasing and edge tones in English as well as that they are able to efficiently use these prosodic features to convey their own discourse intention.

While acoustic studies in the past decade documented a raised /o/ by showing their lowered first formants (F1) almost overlapped with those of high back vowel /u/, no consensus has been made in terms of how this /o/-raising affects the vowels as a system in Seoul Korean. The current study aimed to investigate the age- and gender-related differences of the relative distance among the vowels to better understand the influence of this on-going sound change on the vowel system. We measured the static and dynamic spectral characteristics (F1 and F2) of the seven Korean monophthong vowels /e a ʌ o u ɨ i/ in the spontaneous speech of Seoul Corpus, and depicted the patterns of 30 individual speakers (10 speakers in each group of teens, 20s and 40s) as a function of age and gender. The static spectral examination showed low F1 values of /o/ in the spontaneous speech corpus confirming the vowel /o/ raising, and also revealed greater F2 values of /u, ɨ/ suggesting their anterior articulations. The tendencies were stronger when the speakers were younger and female. The spectral trajectories further showed that the F1 and F2 between /o/ and /u/ were differentiated throughout the vowel mid-point although the trajectories gradually merged near the vowel mid point in the older male speakers' productions. The acoustic evidence of contrast among /o, u, ɨ/ supports that the raised /o/ is not indicative of a merger with /u/ but rather implying a chain-like vowel shift in the Seoul Korean.

The present study investigates the perception of Korean phonation types by native speakers of Aymara. Perception tests were conducted on two sets of Korean speech materials to determine correspondence between Korean and Aymara 3-way contrasts and to find out which of the consonantal and vocalic part of the syllable is more influential in the perception of Korean phonation types. A set of manipulated stimuli, as well as a set of 12 spontaneous words, were prepared for the tests. The first syllable of the 12 Korean bisyllabic words of 3 series of phonation types(Lenis, Aspirated, and Fortis) in 4 places of articulation were split into consonantal and vocalic parts. And then the two parts were combined to form 9 tokens of CV sequences respectively for each place of articulation. Native speakers of Aymara were forced to match Korean stimuli with one of the 15 Aymara words which represent 3 series of consonant types(plain, aspirated, and ejective) in 5 places of articulation(bilabial, alveolar, palatal, velar, and uvular). Results showed that the consonantal part is more influential than the vocalic part to the Aymara subjects' perception of Korean phonation types when the consonantal part is Aspirated in its phonation type, but the vocalic part is more influential than the consonantal part when the consonantal part is Lenis or Fortis in its phonation type. Response analysis showed that Aymara subjects tend to match Korean stops to Aymara ones in such a way that Lenis corresponds to aspirated, Aspirated to aspirated, and Fortis to plain.

Twenty five English native speakers with two different L2 experienced groups and nineteen native Koreans heard both Korean word-initial nasals (/m/ and /n/) in three vowel contexts (low, mid, and high) produced by a native Korean speaker. The experiment examined the hypothesis that Korean nasals are more likely to be judged or perceived correctly by the L2-experienced English learners of Korean than the unexperienced counterparts. The result showed that L2 experienced group was more sensitive to effects of vowel height in judging the Korean nasals in which the perception of nasals before the high vowels was more subject to it. In addition, place of nasal articulation causes asymmetry relations - bilabial nasal /m/ is more likely to be perceived as plosives rather than alveolar nasal /n/. The study found that the L2 experience has a somewhat limited role in perceiving the nasals correctly in the word-initial position, especially before the high vowels, in that even the L2 experienced English subjects have difficulty in identifying the Korean nasals correctly in this environment. Nevertheless, low L2 proficiency might be accounted for the difficulty in the bilabial nasal identification observed by the L2 experienced group.

The purpose of this study is to investigate the effect of Japanese(L1) on the production of Korean accentual phrases(L2). Korean and Japanese have a similar prosodic structure. But different from Korean, Japanese is a pitch accent language. So each word has its own pitch accent. And pitch accents are maintained in the sentence intonation. This difference will have a negative influence on the production of Korean sentence intonation. For this study 4 Korean natives speakers and 10 advanced Japanese learners of Korean participated in the production test. The material analysed constituted 11 Korean sentences, six of which contain formally identical Sino-Korean and Sino-Japanese words. The results show that the initial pitch pattern of Korean accentual phrases was affected by Japanese pitch accent types and this interference was greater for formally identical Sino-Korean and Sino-Japanese words. But besides initial tones of accentual phrase, some positive interference was observed in the internal tonal pattern of accentual phrase. In the phonetic realization, the internal pitch range and initial pitch rising of accentual phrases was greater for Japanese learners of Korean than native speakers of Korean.

The purpose of this study aimed to examine the perceptual pattern of the Korean coda consonants by Chinese learners of Korean. Given that Mandarin allows only two nasals (/n, ŋ/) in the coda position, it was predicted that Chinese learners of Korean had difficulty in discriminating Korean coda consonants. In the experiment, the subjects were 21 beginner-level Chinese learners of Korean. They participated in the discrimination task four times a year in which they were asked to choose the right Korean coda consonants after listening the word from Korean native speakers. The results demonstrated that 1) Chinese learners of Korean improved their perception of the Korean coda consonants. 2) But Chinese learners of Korean performed differently according to the type of Korean coda consonants. Korean consonants /n, p, k, m/ showed significant differences, but /l, ŋ, t/ did not.

The purpose of this work is to analyze and synthesize the pseudo-periodicity of voice using a source model. A speech signal has periodic characteristics; however, it is not completely periodic. While periodicity contributes significantly to the production of prosody, emotional status, etc., pseudo-periodicity contributes to the distinctions between normal and abnormal status, the naturalness of normal speech, etc. Measurement of pseudo-periodicity is typically performed through parameters such as jitter and shimmer. For studying the pseudo-periodic nature of voice in a controlled environment, through collected natural voice, we can only observe the distributions of the parameters, which are limited by the size of collected data. If we can generate voice samples in a controlled manner, experiments that are more diverse can be conducted. In this study, the probability distributions of vowel pitch variation are obtained from the speech signal. Based on the probability distribution of vocal folds, pulses with a designated jitter value are synthesized. Then, the target and re-analyzed jitter values are compared to check the validity of the method. It was found that the jitter synthesis method is useful for normal voice synthesis.

This paper presents a CART(Classification and Regression Tree)-based model to diagnose mental fatigue using speech technology. The parameters used in the model are the significant speech parameters highly correlated to the fatigue and questionnaire responses obtained before and after imposing the fatigue. It is shown from the experiments that the proposed model achieves classification accuracies of 96.67% and 98.33% using the speech parameters and questionnaire responses, respectively. This implies that the proposed model can be used as a tool to diagnose the mental fatigue, and that speech technology is useful to diagnose the fatigue.

This paper aims to propose articulatory features as novel predictors for automatic pronunciation assessment of English produced by Korean learners. Based on the distinctive feature theory, where phonemes are represented as a set of articulatory/phonetic properties, we propose articulatory Goodness-Of-Pronunciation(aGOP) features in terms of the corresponding articulatory attributes, such as nasal, sonorant, anterior, etc. An English speech corpus spoken by Korean learners is used in the assessment modeling. In our system, learners' speech is forced aligned and recognized by using the acoustic and pronunciation models derived from the WSJ corpus (native North American speech) and the CMU pronouncing dictionary, respectively. In order to compute aGOP features, articulatory models are trained for the corresponding articulatory attributes. In addition to the proposed features, various features which are divided into four categories such as RATE, SEGMENT, SILENCE, and GOP are applied as a baseline. In order to enhance the assessment modeling performance and investigate the weights of the salient features, relevant features are extracted by using Best Subset Selection(BSS). The results show that the proposed model using aGOP features outperform the baseline. In addition, analysis of relevant features extracted by BSS reveals that the selected aGOP features represent the salient variations of Korean learners of English. The results are expected to be effective for automatic pronunciation error detection, as well.

This study investigates the acoustic-phonetic features and speech intelligibility of Lombard speech in children with intellectual disability, by examining the effect of Lombard speech at 3 levels of non-noise, 55dB, and 65dB. Eight children with intellectual disability read sentences and played speaking games, and their speech were analyzed in terms of intensity, pitch, vowel space of /a/, /i/, and /u/, VAI(3), articulation rate and speech intelligibility. Results showed, first, that intensity and pitch increased as noise level increased; second, that VAI(3) increased as the noise level increased; third, that articulation rate decreased as noise intensity increased; finally, that speech intelligibility increased as noise intensity increased. The Lombard speech changed the VAI(3), vowel space, articulation rate, speech intelligibility of the children with intellectual disability as well. This study suggests that the Lombard speech will be clinically useful for the persons who have intellectual disability and difficulties in self-control.

This study investigates the relationship between dysphonia severity index(DSI) and voice handicap index(VHI). Seventeen patients with a vocal nodule and twenty patients with laryngopharyngeal reflux(LPR) patients participated in this study. Results showed that there is no significant difference in either DSI or VHI between vocal nodule and LPR patients, with a weak negative correlation between DSI and VHI. Results also showed that there is significant difference only in both MPT and Fhi of all DSI parameters between vocal nodule and LPR patients. These results suggest that voice evaluation should be conducted both objectively in terms of acoustical and aerodynamic parameters and subjectively in terms of GRBAS and VHI.

This study analyzes the characteristics of good impression using speech manipulation scripts and investigates the characteristics of preferred speech voice. Fourty male and female college students participated in this study. They have been exposed to the Gyeongsang dialect spoken by their friends and family for more than 15 years. Two sample voices(1 male and 1 female), considered as giving good impression, were subject to voice analysis. Two students were asked to read the sample paragraph of 'Walking' and their voice samples were analyzed through Praat. The collected speech data were manipulated into 4 different sets by changing pitch level, degree of loudness and speech rate. First, both men and women received good impression more from pitch-lowered sound than from the original one. Second, men tended to receive good impression more from slightly louder voice than from the natural-pitched one. Third, it was shown that men often felt more drowned to a voice at slightly faster speech rate than at the original speech rate. Overall, both male and female listeners favored lower pitch over the original pitch. Men tended to prefer louder voice sound while women preferred less loud one. Men received better impression at a lower speech rate but women at a faster speech rate.