Perceptual Experiment on Number Production for Speaker Identification

Yang, Byunggon 한국음성과학회 2001 음성과학 Vol.8 No.1

The acoustic parameters of nine Korean numbers were analyzed by Praat, a speech analysis software, and synthesized by en ynPPC, a Matt formant synthesizer. The overall intensity, pitch and ferrnant values of the numbers were modified dynamically by a step of 1 dB, 1 Hz and 2.5 respectively. The study explored the sensitivity of listeners to changes in the three acoustic parameters. Twelve subjects (male and female) listened to 390 pairs of synthesized numbers and judged whether the given pair sounded the same or different. Results showed that subjects perceived the same sound quality within the range of 6.6 dB of intensity variation, 10.5 Hz of pitch variation and 5,9 of the fiat three formant variations. The male and female groups showed almost the same perceptual ranges, Also, an asymmetrical structure of high and low boundary was observed. The ranges may be applicable to the development of a speaker identification system while the method of synthesis modification may apply to its evaluation data.

Formant Trajectories of English High Tense and Lax Vowels Produced by Korean and American Speakers

Byunggon Yang 한국언어학회 2010 언어 Vol.35 No.2

Previous studies on the pronunciation of English vowels reported that Korean learners had difficulty producing English tense and lax vowel pairs distinctively. The acoustic comparisons of those studies are mostly based on formant measurements at a single slice of a given vowel section. However, the English vowels usually show dynamic spectral changes across the segment, and only partial data on the vowel segment may be insufficient. The purpose of this paper is to compare the dynamic formant trajectories of English high tense and lax vowel pairs produced by twenty Korean and American males and females. Results showed that the American males and females produced the tense and lax pairs much more distinctly than the Korean counterparts did. Many fine-grained differences along the six measurement points were observed both in the formant trajectories and on the vowel space. These results suggest that more detailed analysis be required in the cross-linguistic comparison of English vowels. Also, the Korean speakers should pay more attention to the dynamic movements of formants in addition to the jaw and tongue positions in order to match those of the American speakers.

Reduction and Frequency Analyses of Vowels and Consonants in the Buckeye Speech Corpus

Yang Byunggon 한국음성학회 2012 말소리와 음성과학 Vol.4 No.3

The aims of this study were three. First, to examine the degree of deviation from dictionary prescribed symbols and actual speech made by American English speakers. Second, to measure the frequency of vowel and consonant production of American English speakers. And third, to investigate gender differences in the segmental sounds in a speech corpus. The Buckeye Speech Corpus was recorded by forty American male and female subjects for one hour per subject. The vowels and consonants in both the phonemic and phonetic transcriptions were extracted from the original files of the corpus and their frequencies were obtained using codes of a free software R. Results were as follows: Firstly, the American English speakers produced a reduced number of vowels and consonants in daily conversation. The reduction rate from the dictionary transcriptions to the actual transcriptions was around 38.2%. Secondly, the American English speakers used more front high and back low vowels while three-fourths of the consonants accounted for stops, fricatives, and nasals. This indicates that the segmental inventory has nonlinear frequency distribution in the speech corpus. Thirdly, the two gender groups produced vowels and consonants similarly even though there were a few noticeable differences in their speech. From these results we propose that English teachers consider pronunciation education reflecting the actual speech sounds and that linguists find a way to establish unmarked segmentals from speech corpora.

Phoneme distribution and syllable structure of entry words in the CMU English Pronouncing Dictionary

Yang, Byunggon Korean Society of Speech Sciences 2016 말소리와 음성과학 Vol.8 No.2

This study explores the phoneme distribution and syllable structure of entry words in the CMU English Pronouncing Dictionary to provide phoneticians and linguists with fundamental phonetic data on English word components. Entry words in the dictionary file were syllabified using an R script and examined to obtain the following results: First, English words preferred consonants to vowels in their word components. In addition, monophthongs occurred much more frequently than diphthongs. When all consonants were categorized by manner and place, the distribution indicated the frequency order of stops, fricatives, and nasals according to manner and that of alveolars, bilabials and velars according to place. These results were comparable to the results obtained from the Buckeye Corpus (Yang, 2012). Second, from the analysis of syllable structure, two-syllable words were most favored, followed by three- and one-syllable words. Of the words in the dictionary, 92.7% consisted of one, two or three syllables. This result may be related to human memory or decoding time. Third, the English words tended to exhibit discord between onset and coda consonants and between adjacent vowels. Dissimilarity between the last onset and the first coda was found in 93.3% of the syllables, while 91.6% of the adjacent vowels were different. From the results above, the author concludes that an analysis of the phonetic symbols in a dictionary may lead to a deeper understanding of English word structures and components.

Pitch trajectories of English vowels produced by American men, women, and children

Yang, Byunggon 한국음성학회 2018 말소리와 음성과학 Vol.10 No.4

Pitch trajectories reflect a continuous variation of vocal fold movements over time. This study examined the pitch trajectories of English vowels produced by 139 American English speakers, statistically analyzing their trajectories using the Generalized Additive Mixed Models (GAMMs). First, Praat was used to read the sound data of Hillenbrand et al. (1995). A pitch analysis script was then prepared, and six pitch values at the corresponding time points within each vowel segment were collected and checked. The results showed that the group of men produced the lowest pitch trajectories, followed by the groups of women, boys, then girls. The density line showed a bimodal distribution. The pitch values at the six corresponding time points formed a single dip, which changed gradually across the vowel segment from 204 to 193 to 196 Hz. The normality tests performed on the pitch data rejected the null hypothesis. Nonparametric tests were therefore conducted to discover the significant differences in the values among the four groups. The GAMMs, which analyzed all the pitch data, produced significant results among the pitch values at the six corresponding time points but not between the two groups of boys and girls. The GAMMs also revealed that the two groups were significantly different only at the first and second time points. Accordingly, the methodology of this study and its findings may be applicable to future studies comparing curvilinear data sets elicited by experimental conditions.

Phoneme distribution and syllable structure of entry words in the CMU English Pronouncing Dictionary

Byunggon Yang 한국음성학회 2016 말소리와 음성과학 Vol.8 No.2

This study explores the phoneme distribution and syllable structure of entry words in the CMU English Pronouncing Dictionary to provide phoneticians and linguists with fundamental phonetic data on English word components. Entry words in the dictionary file were syllabified using an R script and examined to obtain the following results: First, English words preferred consonants to vowels in their word components. In addition, monophthongs occurred much more frequently than diphthongs. When all consonants were categorized by manner and place, the distribution indicated the frequency order of stops, fricatives, and nasals according to manner and that of alveolars, bilabials and velars according to place. These results were comparable to the results obtained from the Buckeye Corpus (Yang, 2012). Second, from the analysis of syllable structure, two-syllable words were most favored, followed by three- and one-syllable words. Of the words in the dictionary, 92.7% consisted of one, two or three syllables. This result may be related to human memory or decoding time. Third, the English words tended to exhibit discord between onset and coda consonants and between adjacent vowels. Dissimilarity between the last onset and the first coda was found in 93.3% of the syllables, while 91.6% of the adjacent vowels were different. From the results above, the author concludes that an analysis of the phonetic symbols in a dictionary may lead to a deeper understanding of English word structures and components.

An Analysis of the English l Sound Produced by Korean Students

Byunggon Yang 한국음성학회 2008 음성과학 Vol.15 No.1

The purpose of this study was to examine the English l sound in an English short story produced by 16 Korean students in order to determine various allophones of the sound using acoustic visual displays and perceptual judgments. The subjects read the story in a quiet office at normal speed. Each word included the lateral sound in onset or coda positions and before a vowel of the following word. Results showed as follows: Firstly, there was a durational difference between the two major groups. Also the majority of the subjects produced the clear l regardless of the contexts. Some students produced the sound as the Korean flap or the English glide [r]. A few missing cases were also seen. The dark l was mostly produced by the subjects of English majors in coda position with a few cases before a vowel in a phrase. Visual displays using the computer analysis were very helpful in distinguishing lateral variants but sometimes perceptual process would be necessary to judge them in fast and weak production of the target word. Further studies would be desirable to test the discrepancies between the acoustical and perceptual decisions.

An evaluation of Korean students’ pronunciation of an English passage by a speech recognition application and two human raters

Byunggon Yang 한국음성학회 2020 말소리와 음성과학 Vol.12 No.4

This study examined thirty-one Korean students’ pronunciation of an English passage using a speech recognition application, Speechnotes, and two Canadian raters’ evaluations of their speech according to the International English Language Testing System (IELTS) band criteria to assess the possibility of using the application as a teaching aid for pronunciation education. The results showed that the grand average percentage of correctly recognized words was 77.7%. From the moderate recognition rate, the pronunciation level of the participants was construed as intermediate and higher. The recognition rate varied depending on the composition of the content words and the function words in each given sentence. Frequency counts of unrecognized words by group level and word type revealed the typical pronunciation problems of the participants, including fricatives and nasals. The IELTS bands chosen by the two native raters for the rainbow passage had a moderately high correlation with each other. A moderate correlation was reported between the number of correctly recognized content words and the raters’ bands, while an almost a negligible correlation was found between the function words and the raters’ bands. From these results, the author concludes that the speech recognition application could constitute a partial aid for diagnosing each individual’s or the group’s pronunciation problems, but further studies are still needed to match human raters.

The f0 distribution of Korean speakers in a spontaneous speech corpus

Byunggon Yang 한국음성학회 2021 말소리와 음성과학 Vol.13 No.3

The fundamental frequency, or f0, is an important acoustic measure in the prosody of human speech. The current study examined the f0 distribution of a corpus of spontaneous speech in order to provide normative data for Korean speakers. The corpus consists of 40 speakers talking freely about their daily activities and their personal views. Praat scripts were created to collect f0 values, and a majority of obvious errors were corrected manually by watching and listening to the f0 contour on a narrow-band spectrogram. Statistical analyses of the f0 distribution were conducted using R. The results showed that the f0 values of all the Korean speakers were right-skewed, with a pointy distribution. The speakers produced spontaneous speech within a frequency range of 274 ㎐ (from 65 ㎐ to 339 ㎐), excluding statistical outliers. The mode of the total f0 data was 102 ㎐. The female f0 range, with a bimodal distribution, appeared wider than that of the male group. Regression analyses based on age and f0 values yielded negligible R-squared values. As the mode of an individual speaker could be predicted from the median, either the median or mode could serve as a good reference for the individual f0 range. Finally, an analysis of the continuous f0 points of intonational phrases revealed that the initial and final segments of the phrases yielded several f0 measurement errors. From these results, we conclude that an examination of a spontaneous speech corpus can provide linguists with useful measures to generalize acoustic properties of f0 variability in a language by an individual or groups. Further studies would be desirable of the use of statistical measures to secure reliable f0 values of individual speakers.

Phonological processes of vowels from orthographic to pronounced words in the Buckeye Corpus by sex and age groups

Byunggon Yang 한국음성학회 2018 말소리와 음성과학 Vol.10 No.2

This paper investigated the phonological processes of monophthongs and diphthongs in the pronounced words present in the Buckeye Corpus and compared the frequency distribution of these processes by sex and age groups to provide a clearer understanding of spoken English to linguists and phoneticians. Both orthographic and pronounced words were extracted from the transcribed label scripts of the Buckeye Corpus using R. Next, the phonological processes of monophthongs and diphthongs in the orthographic and pronounced labels were tabulated using R scripts, and a frequency distribution by vowel process types, as well as sex and age groups, was created. The results revealed that 95% of the orthographic words contained the same number of syllables, whereas 5% had different numbers of vowels, thereby proving that speakers tend to preserve vowels in spontaneous speech. In addition, deletion processes were preferred in natural speech. Most vowel deletions occurred with an unstressed syllable. Chi-square tests were performed to calculate dependence in the distribution of phonological process types for male and female groups and young and old groups. The results showed a very strong correlation. This finding indicates that vowel processes occurred in approximately the same pattern in natural and spontaneous speech data regardless of sex and age, as well as whether or not the vowel processes were identical. Based on these results, the author concludes that an analysis of phonological processes in spontaneous speech corpora can greatly enhance practical understanding of spoken English.