• 대한음성학회:학술대회논문집
• /
• 대한음성학회 2006년도 추계학술대회 발표논문집
• /
• pp.92-95
• /
• 2006

The purpose of this study is to find the acoustic parameters on frequency domain to distinguish the Korean nasals, /m, n, ng/ from each other. Since it is not easy to characterize the antiformant on frequency domain, we suggest the new parameters that are calculated by LTAS(Long term average spectrum). Maximum energy value and its frequency and minimum energy and its frequency of zero are obtained from the spectrum respectively. In addition, slope1, slope2, total energy value, centroid, skewness, and kurtosis are suggested as new parameters as well. The parameters that are revealed as to be statistically signigicant difference are roughly peak1_a, zero_f, slope_1, slope_2, highENG, zero_ENG, and centroid.

• 음성과학
• /
• 제7권3호
• /
• pp.53-68
• /
• 2000

Although Korean stops and affricates show a three-way contrast of phonemes into lax, tense and aspirated, Korean fricatives have only two types, so-called 'lax' and tense. Considering that all the other obstruents maintain a three-way distinction but fricatives, it might be interesting to investigate whether the lax fricatives are really 'lax' in their phonetic and phonological realizations, as assumed. From an acoustic analysis, I found that Korean lax fricatives had a heavy aspiration along with a high pitch for the following vowel, being more comparable to the aspirated category. By contrast, their durational properties were found to be short, or lax-like. In other words, Korean lax fricatives are phonetically neither lax nor aspirated, but both. This dual nature of the lax fricatives takes a better account of the fact that why lax fricatives are subject to tensification, but not aspiration phonologically. Is that simply because there is no aspirated fricative in Korean? I suggest that Korean lax fricatives undergo tensification because of their being short in duration, and that they are not subject to the aspiration rule because they are indeed aspirated sounds.

• 말소리와 음성과학
• /
• 제3권1호
• /
• pp.67-75
• /
• 2011

In Korean, 'Aspiration Merger' is the result of the heteromorphemic sequence of lenis stop and /h/ becoming a single aspirated stop word-medially. However, the contrast between lenis stop-plus-/h/ and an underlying aspirated stop is maintained when they span Phonological Phrase boundaries. By varying the position in the prosodic domain such as APP (Across Phonological Phrase) and PPM (Phonological Phrase Medial) positions, the phonetic properties of the two categories are compared. In the results from noise duration and change of intensity, lenis stop-plus-/h/ show a large difference between the APP and PPM positions. The results from a noise duration comparison show that the two categories are completely neutralized into aspirated stop in the PPM position and the complete neutralization is sensitive to prosodic phrasing.

• 말소리와 음성과학
• /
• 제10권4호
• /
• pp.127-134
• /
• 2018

This study aims to explain the difficulties children with articulation and phonological disorders have in producing alveolar fricative sounds. The study will perform a comparative analysis revealing how ordinary children produce alveolar fricative sounds through five different acoustic variables, and consequently identifying objective differences, compared to children with articulation and phonological disorders. Therefore, this study compared and analyzed the differences between 10 children with articulation and phonological disorders and 10 ordinary children according to a phonation type of alveolar fricative sounds (/s/ and /$s^*$), a type of vowel (/i/, /ε/, /u/, /o/, /ɯ/, /ʌ/, /ɑ/), and a structure of syllables (CV, VCV) through acoustic variables including a central moment, skewness, kurtosis, a center of gravity and variance. That is, children with articulation and phonological disorders, when compared to ordinary children, have difficulties with concentrating an agile and momentary friction with strength when articulating alveolar fricative sounds, which uses strong energy and accompany tension. Furthermore, the values of alveolar fricative sounds of children with articulation and phonological disorders appeared to spread evenly over the average range, which means that the range of overall the standard deviation values for children with functional phonological disorders is wider than that of ordinary children. For a future study, if the mispronounced sounds relating to omission, substitution, and addition can be compared and analyzed for various target groups, it could be used effectively to help children with functional phonological disorders.

• 말소리와 음성과학
• /
• 제4권2호
• /
• pp.89-94
• /
• 2012

The aim of this study is to investigate the usefulness of the parameter CPP (cepstral peak prominence) and LTAS (long term average spectrum) band energy for an analysis of breathy voice with vocal fold paralysis. Thirty-four female subjects who have vocal paralysis after thyroidectomy participated in this study. According to the perceptual judgements by three speech pathologists and one phonetic scholar, subjects were divided into two groups: breathy voice group (n = 21) and non-breathy voice group (n = 13). Maximum sustained phonation task was measured for acoustic analysis. CPP-related (i.e. mean F0, mean CPP, and mean CPPs) and LTAS-related (i.e. minimum, maximum, and mean) parameters were used. Independent samples t-test was conducted. Regarding CPP, there are significant differences in mean CPP and mean CPPs between groups. The values of mean CPP and CPPs in the non-breathy voice group are higher than those in the breathy voice group. The CPP could be regarded as the useful parameter for breathy voice analysis in the clinic. When it comes to LTAS, energy from 0 to 2 kHz are significantly different between groups. The minimum value of non-breathy group is lower than that of breathy group, whereas the maximum value of non-breathy group is higher. The frequency band below 2 kHz seems to be related to breathy voice.

• 대한음성학회지:말소리
• /
• 제38호
• /
• pp.71-97
• /
• 1999

In this paper I have surveyed vowel phonemes in a variety of English accents and have proposed the vowel systems of English. The English accents covered in this paper include General American English, Northeastern American English, Western American English, Southern British English, Northern British English, Scottish English, Southern Irish English, Northern Irish English, Australian English, and New Zealand English. The vowel systems proposed here reflect the acoustic information of vowels and phonological aspects of English. This paper offers an Optimality Theory-based analysis of the English vowel systems by appealing to independently motivated constraints. This paper, following Flemming(1995), makes an assumption that the vowel system in question is selected in output as an optimal candidate by a given constraint ranking, the assumption which is different from the view that the vowel system is fixed in input. The analysis proposed here gives an answer to why a specific vowel system is selected and why dialectal variations come about. It is shown in this paper that the vowel system selected in a specific dialect comes from an optimal satisfaction of a given constraint ranking and that dialectal differences result from dynamic permutations of the same constraints. The constraint-based analysis proffered here accounts well for the similarities and differences among dialects in regard to the vowel system.

• 대한음성학회:학술대회논문집
• /
• 대한음성학회 1996년도 10월 학술대회지
• /
• pp.514-514
• /
• 1996

Igbo, a new Benue Congo language has a vowel harmony system which, like that of Akan, is based on the pharynx size or tongue root position. In this study we examine Igbo vowel harmony with particular reference to assimilatory patterns of vowels in different harmony sets. This is to gain some insight into the factors involved in Igbo vowel assimilation, and to establish to what extent reports on Akan vowel assimilation are validated in Igbo. Tokens of the eight phonemic vowels of Standard Igbo are recorded from three native speakers of Igbo. The vowels are acoustically investigated (using the LPC analysis of CSL) in individual lexical items and within carefully designed carrier phrases. The F1 and F2 values of the vowels are obtained as these formant values are generally useful in establishing the salient characteristics of vowels. Vowels from the harmony sets are juxtaposed in the carrier phrases to ascertain the extent of assimilation. Results of the investigation show that the F1 values, to a large extend, are enough to characterize these vowels. The (-Expanded) vowels have higher F1 values than their (+Expanded) counterpart. Where there is an overlap in F1 values for some vowels the F1 bandwidth values serve to distinguish between the vowels. The overlap often reported in Akan for /I/ and /e/ on the one hand and /${\mho}$/ and /o/ on the other is not validated in Igbo. While the F1 values for these pairs of vowels are quite similar for one of our speakers, there is an appreciable difference between the F1 values of these vowels for the other two speakers. There is however an overlap for /e/ and /o/ for one of the speakers. Assimilations are generally regressive across word boundaries. It is, however, necessary to point out that the general perceptual impression that one of the vowels completely assimilates to the other, is not borne out by our investigation. Most of our F1 and F2 values for the vowels in individual lexical items are altered in assimilations. This then suggests that assimilation involving these vowels is partial rather than complete. The emerging 'allophones' are acoustically similar to the (+Expanded) vowel involved in the assimilation, that is when vowels from different harmony sets are involved. We conclude that while assimilation of Igbo vowels involves some phonological considerations, phonetic factors appear to be permanent in deciding the final form of the vowels.

• 대한음성학회:학술대회논문집
• /
• 대한음성학회 1996년도 10월 학술대회지
• /
• pp.390-398
• /
• 1996

Acoustic analysis study was performed on 20 normal subjects by speaking nonsense syllables composed of Korean bilabial stops(/p, $p^{*}$/, ph/) and their Preceding and/or following vowel /a/(that is, [pa, $p^{*}a$, pha, apa, $ap^{*}a$, apha]) with an ultraminiature pressure sensor in their mouths. Speech materials were phonated twice, once with a moderate voice, another time with a loud voice. The acoustic signal and intraoral pressure were recorded simultaneously on computer. By these procedures, we were to measure the intraoral pressure, closure duration and VOT of Korean bilabial stops, and to compare the values one another according to the intensity of phonation and the position of the target consonants. Intraoral pressure was measured by the peak intraoral pressure value of its wave; closure duration by the time interval between the onset of intraoral pressure build-up and the burst meaning the release of closure; Voice onset time(VOT) by the time interval between the burst and the onset of glottal vibration. Heavily aspirated bilabial stop consonant /ph/ showed the highest intraoral pressure value, unaspirated /p$^{*}$/, the second, slightly aspirated /p/, the lowest. The syllable initial bilabial stops showed higher intraoral pressure than word initial stops, and the value of loudly phonated consonants were higher than moderate consonants. The longest closure duration period was that of /$p^{*}$/ and the shortest, /p/, and the duration was longer in word initial position and in the moderate voice. In VOT, the order of the longest to shortest was /ph/, /p/, /$p^{*}$/, and the value was shorter when the consonant was in intervocalic position and when it was phonated with a loud voice.

• 대한음성학회:학술대회논문집
• /
• 대한음성학회 1996년도 10월 학술대회지
• /
• pp.207-207
• /
• 1996

The neutral tone is one of the most important distinguishing features in Beijing Mandarin, but there are two completely different views on its linguistic function: a special tone(Xu, 1980) versus weak stress(Chao, 1968). In this paper, the acoustic manifestation of the neutral tone will be explored to show that it is closely related to weak stress. 122 disyllabic words in which the second syllable carries the neutral tone, including 22 stress pairs, were uttered by a native male speaker of Beijing dialect and analysed by Kay Digital Sonagraph 5500-1. The results of the acoustic analysis are presented as follows: 1) The first two formants of the medial and the syllabic vowel moves towards that of central vowel with a greater magnitude in the syllable with the neutral tone than in the syllable with any of the four normal tones. Also the vowel ending, and nasal coda /n/ and / / in the syllable with the neutral tone tends to be deleted. 2) In the syllables with the neutral tone, there are strong carryover coarticulations between the medial and syllabic vowel and the preceding unvoiced consonant. In general, the vowel is affected to move towards the position of the central vowel with more greater magnitude by coronal consonant than by labial or velar consonant. 3) In the syllable with the neutral tone, when and only when it precedes a syllable with tone-4, the high vowel following [f], [ts'], [s], [ts'], [s], [tc'] or [c] tends to be voiceless. 4) It can be seen from the acoustical results of 22 stress pairs that the duration of the syllable with the neutral tone is on the average reduced to 55% of that of the syllable with the four normal tones, and the duration of the final in the syllable with neutral tone is on the average reduced to 45% of that of the final in the syllable with the four normal tones(Lin & Yan 1980). 5) The FO contour of the neutral tone is highly dependent on the preceding normal tone(Lin & Yan 1993). For a number of languages it has been found that the vowel space is reduced as the level of stress placed upon the vowel is reduced(Nord 1986). Therefore we reach the conclusion that the syllable with neutral tone is related to weak stress(Lin & Yan 1990). The neutral tone is not a special tone because the preceding normal tone.

• 대한음성학회:학술대회논문집
• /
• 대한음성학회 1996년도 2월 학술대회지
• /
• pp.9-22
• /
• 1996

Among the various dysarthric subtypes, diagnosis of ataxic dysarthria is rendered when the speech characteristics include imprecise and irregular articulatory breakdowns, marked degree of speech rate impairment, overall monopitch and monoloudness, and respiratory-articulatory incoordination. Traditionally, speech pathologists have relied only upon their ‘ears’ to describe and evaluate the dysarthric speech. A statement of percentage of correct words identified by a listener do not provide so much more than an index of severity. Within the same perceptual dimension, a carefully constructed speech intelligibility test can specify patterns of errors. The patterns can contain a diagnostic value as well as Provide strategies for remediation. The phonetically transcribed texts on single words and a standard passage, 'kail' produced by an ataxic dysarthria are presented in this report, with an emphasis of the articulatory error analysis. Furthermore,, acoustic tools [e.g., spectrography to measure formant transitions, segment durations, consonant spectra, etc.] are utilized to serve as basic measures that objectively document patients' speech intelligibility, Finally, the treatment methods [e.g., spectrography as a visual feedback, gestural reorganization using pacing method, DAF (Delayed Auditory Feedback)] to modify the dysarthric behaviors are presented.