The intent of the present study is to investigate the acoustic properties of Korean /w/ in various phonological contexts, compare them with those of English /w/, and attempt to explain why English /w/'s are perceived differently by Korean speakers depending on the phonological contexts. Experiments 1 and 2 present the acoustic measure of F2 of Korean /w/ in various linguistic positions and show that unlike English /w/, Korean /w/ shows quite a strong coarticulation with the following vowel. Based on these experiments, Experiment 3 investigates why English /w/ is adapted differently into Korean. Specifically, it discusses why English /wain/ is adapted as /wain/ whereas English /twin/ is adapted into Korean as $/t^{h_i}win/$ with an extra vowel. This study argues that the different perception of English /w/ by Korean and English speakers is due to the different F2 transitional pattern of /w/ in Korean and English in various phonological contexts. It also argues that the F2 transitional pattern is an important factor in the perception of /w/.

This paper reports a preliminary result of an acoustic study on the stress and intonational system in Lakhota, a native American language. It investigates how the stress and intonation in Lakhota are phonetically manifested; and how the stress interacts with other prosodic factors. The results preliminarily obtained from one native Lakhota speaker suggest that the primary cue of the stress is relatively high F0 which is often accompanied by higher intensity (for the vowel) and longer VOT (for aspirated stops). The results also indicate that stress is not reliably marked by duration. The stress system, however, interacts with the intonational pattern, such that, for example, intonational peak falls on the stressed syllable with a general pattern of L+H* and that it interacts with the boundary tone L%, resulting in mid tone utterance-finally. This paper can be viewed largely as a qualitative study on an understudied native American language, Lakhota and as forming a basis for further development of its stress and intonation system whose acoustic properties of its prosodic system have not been investigated before.

The aim of this study was to identify pronunciation difficulties of Korean learners of English in their articulation of English sibilants /dg, g, z/. Forty-five syllables were produced five times by twelve college students. Test scores were measured from the score board made by FluSpeak, a speech training software program, which was designed for English pronunciation practice and improvement. Results show that 1) the subjects had lower scores in producing /g/ than /dg/ and /z/ from all positions, and 2) subjects had lower scores in inter-vocalic position than in pre-vocalic position and in post-vocalic position when they produced /dg/, /g/, and /z/. The results suggest that on the whole Korean learners have much difficulty in producing /g/, and they also have more auditory and articulatory problems in intervocalic than in the other positions when they produce these sibilants.

This study examined the acoustic properties of initial stops in Korean, produced by Korean native speakers and English Korean learners. The productions of Korean native speakers were compared with those of beginners and advanced learners of Korean. Fundamental frequency(F0) and Voice Onset Time(VOT) were measured in condition of one or two syllable words, containing word-initial lenis, fortis, and aspirated stops. English Korean Learners showed that they produced stops with relatively shorter VOT and lower F0, compared with those of Korean native speakers. In case of the manner of articulation, English Korean learners have production difficulties in order of lenis stops, aspirated stops, and fortis stops. In regard to the place of articulation, English Korean learners showed production troubles in order of labial stops, velar stops, and alveolar stops. In the experiment of perception, it is hard for English Korean learners to distinguish stops of lenis and aspirated. Therefore, the results of production experiment were almost consistent with those of the perception experiment. Finally, according to both groups of proficiency, the results demonstrated that the advanced learners produce or perceive Korean stops easier than the beginners.

This study aims to describe the vowel system of present-day American English and to discuss some of its phonetic variations due to regional differences. Fifteen speakers of American English from various regions of the United States produced the monophthongs of English. The vowel duration and the frequencies of the first and the second formant were measured. The results indicate that the distinction between the vowels [c] and [a] has been merged in most parts of the U.S. except in some speakers from eastern and southeastern parts of the U.S., resulting in the general loss of phonemic distinction between the vowels. The phonemic merger of the two vowels can be interpreted as the result of the relatively small functional load of the [c]-[a] contrast, and the smaller back vowel space in comparison to the front vowel space. The study also shows that the F2 frequencies of the high back vowel [u] were extremely high in most of the speakers from the eastern region of the U.S., resulting in the overall reduction of their acoustic space for high vowels. From the viewpoint of the Adaptive Dispersion Theory proposed by Liljencrants & Lindblom (1972) and Lindblom (1986), the high back vowel [u] appeared to have been fronted in order to satisfy the economy of articulatory gesture to some extent without blurring any contrast between [i] and [u] in the high vowel region.

This study examines the phonetic realizations of English word stress to identify the influence of experiment method on experiment results. Stimuli uttered by native and Korean ESL beginners in authentic conversations are extracted to be shuffled according to their positions in utterances and information structure. Results indicate that the acoustic characteristics of English word stress are realized depending on its position in utterances. The native speakers correlate the stressed syllables in shorter duration with higher pitch and stronger intensity at sentence-final positions unlike the previous experiments and the traditional definition that stressed syllables are uttered in longer duration with higher pitch and stronger intensity; at sentence-medial positions, the native speakers correlate the stressed syllables in longer duration with higher pitch and no regularity in intensity or in shorter duration with lower pitch and intensity depending on their conversational intention. Korean ESL beginners correlate the stressed syllables in shorter duration regardless of positions in sentences with no regularity in pitch and intensity. This study, thus, shows that a different experiment method may result in different results on the phonetic realizations of English word stress.

The aim of this study is to analyze the tonal structures of Korean conjunctive phrases produced by Daegu dialect speakers and show that there are distinctive intonational patterns between dialogic and reading styles. In the experiment, we examined the pitch contour at the edge of conjunctive phrases including '-ko', $'-(i)my{\partial}n'$, $'-(a){\partial}s{\partial}'$, '-(nin)de', '-do' in the base which is made a coordinate and subordinate conjunctive sentence according to the relation of pre-phrase and post-phrase. The results of this study show that '-ko' has L%, $'-(i)my{\partial}n'$ has LH%, $'-(a){\partial}s{\partial}'$ has HL% and '-(nin)de' has LH%, '-do' has LH% in Daegu Dialect. And the results show the conjunctive sentences were about 20% longer when they produced in a dialogic style than in a reading style. The dialogic style has various durations, the duration of the reading style is slower than the dialogic style by a rate of 20%. This suggests that the dialogic style is more dynamic than the reading style, which may be due to the communicative interaction between speakers and listeners.

This study examined acoustic characteristics of 900 CV syllables produced by five English native speakers. Those target syllables were produced between the syllable /ba/ twenty times. The syllables were segmented and normalized by the maximum intensity value of each syllable and were divided into consonant or vowel sections by a few visible acoustic criteria. Intensity values were collected at 100 relative time points per syllable. Also, cumulative intensity values and consonant and vowel durations along with the ratio of a consonant to each syllable were measured using Praat scripts. Results showed as follows: Firstly, the consonantal section amounted to a quarter of the syllable in terms of both the cumulative intensity and duration. Secondly, the consonantal ratio by the cumulative intensity was similar to that by the duration. Finally, the sum of the cumulative intensity values in each syllable partially coincided with the consonant order by the current sonority scale. Further studies would be desirable on more reliable acoustical measurements and sophisticated perceptual experiments on the English syllables.

Recently, many researchers have been interested in children with phonological disorders. The purpose of this study was to examine those children in comparison with normal children and to find better assessment criteria of the whole-word approach. Three children with phonological disorders and three normal children of 5 to 7 years old participated in the picture description tasks. Results of this study were as follows: there was a significant difference in the whole-word assessment between normal and phonological disorder children. Such criteria as whole-word correctness, whole-word complexity, whole-word intelligibility proved to be good for diagnosing children's phonological disorders. Further studies would be desirable to apply the approach to more children of various age groups.

Speech-language therapist's experiences of their clinical practice offer greater insight to develop the assessment model for resonance disorders appropriate to the clinical setting. In order to investigate their experiences of resonance disorders qualitatively, a semi-structured interview questionnaire was developed on the basis of the review of the literatures about the assessment procedures. From the interviews with 4 speech therapists analysed by using a qualitative, constant-comparative method, 3 main themes were derived: (1) the currently accepted definitions and characteristics of the resonance disorders, (2) the status quo of the assessment procedures, and (3) the needs for the improvement of the assessment procedures. In addition, 15 sub-themes were emerged from the 3 main themes. All themes mentioned by the therapists provide the directions for the development of comprehensive and valid assessment model for the resonance disorders in Korea.

In an effort to enhance the quality of feature vector classification and thereby reduce the recognition error rate of the speaker-independent speech recognition, we employ the Mahalanobis distance in the calculation of the similarity measure between feature vectors. It is assumed that the metric matrix of the Mahalanobis distance be diagonal for the sake of cost reduction in memory and time of calculation. We propose that the diagonal elements be given in terms of the variations of the feature vector components. Geometrically, this prescription tends to redistribute the set of data in the shape of a hypersphere in the feature vector space. The idea is applied to the speech recognition by hidden Markov model with fuzzy vector quantization. The result shows that the recognition is improved by an appropriate choice of the relevant adjustable parameter. The Viterbi score difference of the two winners in the recognition test shows that the general behavior is in accord with that of the recognition error rate.

The speech synthesis technology is widely used and its application area is also being broadened to an automatic response service, a learning system for handicapped person, etc. However, the sound quality of the speech synthesizer has not yet reached to the satisfactory level of users. To make a synthesized speech, the existing synthesizer generates rhythms only by the interval information such as space and comma or by several punctuation marks such as a question mark and an exclamation mark so that it is not easy to generate natural rhythms of people even though it is based on mass speech database. To make up for the problem, there is a way to select rhythms after processing language from a higher level information. This paper proposes a method for generating tags for controling rhythms by analyzing the meaning of sentence with speech situation information. We use the Systemic Functional Grammar (SFG) [4] which analyzes the meaning of sentence with speech situation information considering the sentence prior to the given one, the situation of a conversation, the relationship among people in the conversation, etc. In this study, we generate Semantic Speech Control Tag (SSCT) by the result of SFG's meaning analysis and the voice wave analysis.