• Phonetics and Speech Sciences
• /
• v.15 no.1
• /
• pp.1-7
• /
• 2023

This study investigated the influences of probabilistic accessibility of the word being produced - as determined by its usage frequency and neighborhood density - on native and high-proficiency L2 speakers' realization of six English monophthong vowels. The native group hyperarticulated the vowels over an expanded acoustic space when the vowel occurred in words with low frequency and high density, supporting the claim that vowel forms are modified in accordance with the probabilistic accessibility of words. However, temporal expansion occurred in words with greater accessibility (i.e., with high frequency and low density) as an effect of low phonotactic probability in low-density words, particularly in attended speech. This suggests that temporal modification in the opposite direction may be part of the phonetic characteristics that are enhanced in communicatively driven focus realization. Conversely, none of these spectral and temporal patterns were found in the L2 group, thereby indicating that even the high-proficiency L2 speakers may not have developed experience-based sensitivity to the modulation of sub-categorical phonetic details indexed with word-level probabilistic information. The results are discussed with respect to how phonological representations are shaped in a word-specific manner for the sake of communicatively driven lexical intelligibility, and what factors may contribute to the lack of native-like sensitivity in L2 speech.

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

• Phonetics and Speech Sciences
• /
• v.6 no.1
• /
• pp.31-38
• /
• 2014

The current study presents an instrumental phonetic analysis of Korean monophthong vowels in the early twentieth century Seoul Korean, based on audio recordings of elementary school textbooks Botonghakgyo Joseoneodokbon (Korean Reading Textbook for Elementary School). The data examined in this study were a list of the Korean mono syllables (Banjeol), and a short passage, recorded by one 41-year-old male speaker in 1935, as well as a short passage recorded by one 11-year-old male speaker in 1935. The Korean monophthongs were examined in terms of acoustic analysis of the vowel formants (F1, F2) and compared to those recorded by 18 male speakers of Seoul Korean in 2013. The results show that in 1935, 1) /e/ and /ɛ/ were clearly separated in the vowel space; 2) /o/ and /u/ were also clearly separated without any overlapping values; 3) some tokens of /y/ and /ø/ were produced as monophthongs, not as diphthongs. Based on the results, we can observe the historical change of the Korean vowels over 80-90 years such as 1) /e/ and /ɛ/ have been merged; and 2) /o/ has been raised and overlapped with /u/.

• Journal of Korean language education
• /
• v.28 no.1
• /
• pp.1-21
• /
• 2017

The purpose of this study is to investigate the aspect of production and perception of Korean vowels /${\Lambda}$/ and /o/ and to discuss the correlation between production and perception of the two vowels. For this purpose, two separate experiments were conducted. 19 Chinese learners and 20 Korean native speakers produced Korean vowels /${\Lambda}$/ and /o/. Production experiments indicated that Koreans and Chinese female groups revealed common features in production, showing that they all pronounced /${\Lambda}$/ and /o/ in a distinguishable manner in the acoustic space. On the other hand, the Chinese male group failed to show that they could pronounce two vowels distinctively. The Chinese male group seemed to be confused in vowel height between the two vowels. A perception experiment was carried out on a continuum consisting of 11 synthesized stimuli. The perceptual judgment from referred Chinese and Korean subjects showed that Koreans and Chinese female groups had the same phonological boundaries (stimulus '04') for the two vowels on the continuum. However, the Chinese male group made perceptual criterion on stimulus '03'. These results confirmed that there was strong correlation between the aspect of production and perception.

• Phonetics and Speech Sciences
• /
• v.5 no.2
• /
• pp.33-41
• /
• 2013

This is a follow-up study on Han and Kang (2013) which argued that the Euclidean distances between /o/ and /u/ in Seoul Korean decreased in the first syllable position as speakers were among younger female speakers but not for male speakers, whereas in the second syllable position both gender groups showed a cross-generational decreasing effect of the Euclidean distance between /o/ and /u/. This study normalized the same data in Han and Kang (2013) which measured 12 speakers (six males and six females) for each Age group and investigated the spectral changes vowels /o/ and /u/ between age and gender, using the log-mean normalized statistical results. This study also examined overlap fraction values generated in SOAM 2D ($F1{\times}F2$) (cf. Wassink, 2006), which may also indicate the proximity of two vowels in question. The results showed that /o/ and /u/ vowels were making closer with /o/ raising for female speakers in $V_1$ and $V_2$ positions but only in the $V_2$ position for male speakers. That is, females led the upward movement of peripheral /o/ vowel, just like the raising of 'e' and 'o' in New York City (Labov, 1991). The results also showed that younger speakers used a rather narrow vowel space for the vowels. This also contributed to the proximity of the vowels /o/ and /u/, resulting in rather large overlap fraction values for younger speakers between these two vowels.

• Phonetics and Speech Sciences
• /
• v.9 no.3
• /
• pp.75-83
• /
• 2017

The purpose of this study is to find clues to the risk of voice disorders in soprano students. The subjects of the study were 17 soprano students and 18 general students (women). The phonation of vowels /a/, /i/, and /u/ with C4 and F4 notes in each group were recorded. Then, only soprano students were made to record their classical vocalization containing vibrato. Formant, formant energy, bandwidth, VAI (vowel area index), VSA (vowel space area) and L/H ratio were analyzed. There was significant difference in F3 such that the singers' note was measured around 3 kHz which seems to be 400 Hz higher than one from general students. But, There was no significant difference in L/H ratio between soprano student and the general student. There was a significant difference in F3 in the comparison of the soprano students' two vocalization methods. Classical vocalization was measured at 200Hz higher than sustained phonation in F3. Vocal tract adjustment was made and vowel space changed, but there was no significant difference in F3 energy, which is the index of singers' formant according to the phonation method. The L/H ratio, which can be a direct indicator of vocal effort, has no difference in phonation method and is lowered in all phonation methods as the pitch increases. C4 and F4 pitches are lower than the singing range of the soprano. When the pitch changes, vocal effort increases like a general student which will be an indicator of the risk of vocalization. This will be a clue to the vocalization of the immature soprano student.

• Speech Sciences
• /
• v.14 no.4
• /
• pp.203-212
• /
• 2007

This study was to compare some acoustic characteristics of vowels produced by children with cochlear implant (CI) and the children with normal hearing. 20 subjects under ten years old were further classified into two groups (one group of CI children under four years old and the other group of CI children over four years old). For the normal hearing group, 20 subjects are participated in the experiment. Some acoustic parameters including fundamental frequency (F0) and formant frequencies (F1, F2) were measured in the two groups according to the age of cochlear implant operation. For the CI group, three comer vowels (/a/, /i/, /u/) were recorded five times in isolation and analyzed with Multi-Speech (Kay Elemetrics, model 3700), and two independent t-tests on their formant data were conducted using SPSS 11.5. The result showed that the implanted group over four years had a significant difference in F0 and F1 comparing with the implanted group under four years of age as well as the normal hearing group. Those values of the children with the implanted group under four years old were closer to those of the children with the normal hearing. As to the F2, there was no significant difference among implanted groups. However, it was shown that the vowel space for the implanted groups regardless the operation age indicated much smaller than that for the normal hearing children. This acoustic results suggest that CI surgery would be much more effective if it is done under the age of four years old.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.3 no.1
• /
• pp.185-196
• /
• 1999

In this dissertation, a new off-line recognition system is proposed using a subgraph pattern, neural network. After thinning is applied to input characters, balance having a noise elimination function on location is performed. Then as the first step for recognition procedure, circular elements are extracted and recognized. From the subblock HT, space feature points such as endpoint, flex point, bridge point are extracted and a subgraph pattern is formed observing the relations among them. A region where vowel can exist is allocated and a candidate point of the vowel is extracted. Then, using the subgraph pattern dictionary, a vowel is recognized. A same method is applied to extract horizontal vowels and the vowel is recognized through a simple structural analysis. For verification of recognition subgraph in this paper, experiments are done with the most frequently used Myngjo font, Gothic font for printed characters and handwritten characters. In case of Gothic font, character recognition rate was 98.9%. For Myngjo font characters, the recognition rate was 98.2%. For handwritten characters, the recognition rate was 92.5%. The total recognition rate was 94.8% with mixed handwriting and printing characters for multi-font recognition.

• Journal of radiological science and technology
• /
• v.22 no.1
• /
• pp.35-42
• /
• 1999

This study was undertaken to take the correct vocal technique(especially about the resonance of oral cavity). The resonance of oral and pharyngeal cavity is the principle which can vocalize well without any abnormal signs in the throat. Therefore it is important for us to understand how to use the correct resonance of oral and pharyngeal cavity. Shimadzu X-ray remote control TV system and Shimadzu magnet $nex-{\alpha}$ (SMT-50CX/H) were used for checking the movements of T-M joint and diaphragmatic respiration. The results obtained were summerized as follows: 1. While opening T-M joint space like the vowel "A" [a], We should vocalize five fundamental vowel [a,e,i,o,u] with diaphragmatic respiration holded. 2. Diminuendo must be expressed by increasing a breath volume while descending a mandible gradually because we can not ascend maxilla. So we can make a delicate expression. 3. The resonance of oral cavity must be scattered by elevating the soft palatine lightly with relax of throat.

• Proceedings of the KSPS conference
• /
• 2005.11a
• /
• pp.97-100
• /
• 2005

The aim of the present study is to compare the vowel formants between generations in Daegu dialect. 20 Daegu dialect speakers were participated in this study; 10 were in their 40's, the other 10were in their 20's. As a result, the distance of /ㅣ/ and /ㅐ/, and, /ㅡ/ and /ㅓ/ in 20's is further than 40's, while the distance of /ㅗ/ and in 20's is closer than 40's. It seems reasonable to conclude that vowels in Daegu dialect change to have their own stable space, but /ㅗ/ and /ㅜ/ does not.