• MALSORI
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• no.35_36
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• pp.121-129
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• 1998

In this paper, articulatory simulator 'Artsim' is used as a tool for the experiments to examine the articulatory characteristics of 6 different vowels. Each vowels are defined by some articulatory points from their vocal tract area functions and shapes of tongues. Each points are varied systematically to synthesize vowels and the synthesized sound is evaluated by human listners. Finally distributions of each vowels within vowel space is obtained. From the experimental results it is verified that our articulatory simulator can be used effectively to investigate the articulatory characteristics of speech.

• Phonetics and Speech Sciences
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• v.8 no.4
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• pp.103-113
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• 2016

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.

• Speech Sciences
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• v.8 no.1
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• pp.67-76
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• 2001

This study is targeted at introducing the three aspects of speech timing (articulatory, acoustic and auditory) and discussing their strong and weak points in describing speech timing. Traditional (extrinsic) articulatory timing theories exclude timing representation in the speaker's articulatory plan for his utterance, while the (intrinsic) articulatory timing theories headed by Fowler incorporate time into the plan for an utterance. As compared with articulatory timing studies with crucial constraints in data collection, acoustic timing studies can deal with even several hours of speech relatively easily. This enables us to perform suprasegmental timing studies as well as segmental timing studies. On the other hand, perception of speech timing is related to psychology rather than physiology and physics. Therefore, auditory timing studies contribute to enhancing our understanding of speech timing from the psychological point of view. Traditionally, some theories of speech timing (e.g. typology of speech rhythm: stress-timing; syllable-timing or mora-timing) have been based on our perception. However, it is problematic that auditory timing can be subjective despite some validity. Many questions as to speech timing are expected to be answered more objectively. Acoustic and articulatory description of timing will be the method of solving such problems of auditory timing.

• Phonetics and Speech Sciences
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• v.11 no.1
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• pp.19-27
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• 2019

Lateral approximants are well known as having complex articulatory characteristics, which vary cross-linguistically, across speakers, and across utterances. However, less attention has been paid to the articulation of Korean laterals, which do not contrast with a rhotic and may thus exhibit greater-than-normal variability. The focus of this study is to investigate the general articulatory characteristics of the Korean lateral [l] as well as the articulatory variation using novel 3D ultrasound imaging methods. The results of this study revealed significant between-speaker variation and some vowel-dependent variation with regard to the articulation of the Korean lateral [l], which has not been reported previously. Even though all participants in this study showed an anterior occlusion, the place of articulation and the size of the occlusion varied greatly across speakers. The data also revealed that left-right asymmetry is present in the articulation of the Korean lateral. The individual variation of the Korean lateral [l] suggests that it has a large articulatory-acoustic space for variation, since it has no contrasting sound that causes perceptual confusion.

• Phonetics and Speech Sciences
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• v.5 no.1
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• pp.39-46
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• 2013

This study examined the effects of phonetic complexity and articulatory severity on Percentage of Correct Consonant (PCC) and speech intelligibility in adults with dysarthria. Speech samples of thirty-two words from APAC (Assessment of Phonology and Articulation of Children) were collected from 38 dysarthric speakers with one of two different levels of articulatory severities (mild or mild-moderate). A PCC and speech intelligibility score was calculated by the 4 levels of phonetic complexity. Two-way mixed ANOVA analysis revealed: (1) the group with mild severity showed significantly higher PCC and speech intelligibility scores than the mild-moderate articulatory severity group, (2) PCC at the phonetic complexity level 4 was significantly lower than those at the other levels and (3) an interaction effect of articulatory severity and phonetic complexity was observed only on the PCC. Pearson correlation analysis demonstrated the degree of correlation between PCC and speech intelligibility varied depending on the level of articulatory severity and phonetic complexity. The clinical implications of the findings were discussed.

• Speech Sciences
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• v.2
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• pp.45-55
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• 1997

This paper describes the procedure of implementing an articulatory speech simulator, in order to model the human articulatory organs and to synthesize speech from this model after. Images required to construct the vocal tract model were obtained from MRI, they were then used to construct 2D and 3D vocal tract shapes. In this paper 3D vocal tract shapes were constructed by spatially concatenating and interpolating sectional MRI images. 2D vocal tract shapes were constructed and analyzed automatically into a digital filter model. Following this speech sounds corresponding to the model were then synthesized from the filter. All procedures in this study were using MATLAB.

• Phonetics and Speech Sciences
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• v.5 no.3
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• pp.95-101
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• 2013

Aging is related to anatomical and physiological changes in respiratory and phonation organs. These changes influence articulation which leads to inaccurate speech and slow articulatory diadochokinesis(DDK). DDK indicates the range, rate, regularity, accuracy, and agility of articulation that reflect motor speech function. The purpose of this study is to investigate the rates and regularities of DDK in healthy Korean elderly through passive acoustic analysis (Praat). Thirty subjects between the ages of 65 and 94 participated in this study. Rate was observed for 5 seconds, while regularity was calculated based on the standard deviation on the following: 1) syllable duration of each task; 2) gap duration between syllables. Then, simple regression analysis was conducted in order to examine the effect of age on performance. The result showed that the slow rate was not a significant factor in terms of advancing age. Furthermore, regularity indicated a significant difference in the following: 1) /pʌ/, /kʌ/ and /pʌtʌkʌ/ in syllable duration; 2) /kʌ/ duration in the gap between syllables. In conclusion, articulatory coordination is reduced with the onset of aging. In particular, /kʌ/ would be a sensitive task for articulatory coordination.

• The Journal of the Acoustical Society of Korea
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• v.24 no.2E
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• pp.71-76
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• 2005

Compared to normal speech, distant-talking speech is characterized by the acoustic effect due to interfering sound and echoes as well as articulatory changes resulting from the speaker's effort to be more intelligible. In this paper, the acoustic features for distant-talking speech due to the articulatory changes will be analyzed and compared with those of the Lombard effect. In order to examine the effect of different distances and articulatory changes, speech recognition experiments were conducted for normal speech as well as distant-talking speech at different distances using HTK. The speech data used in this study consist of 4500 distant-talking utterances and 4500 normal utterances of 90 speakers (56 males and 34 females). Acoustic features selected for the analysis were duration, formants (F1 and F2), fundamental frequency, total energy and energy distribution. The results show that the acoustic-phonetic features for distant-talking speech correspond mostly to those of Lombard speech, in that the main resulting acoustic changes between normal and distant-talking speech are the increase in vowel duration, the shift in first and second formant, the increase in fundamental frequency, the increase in total energy and the shift in energy from low frequency band to middle or high bands.

• Phonetics and Speech Sciences
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• v.8 no.3
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• pp.31-38
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• 2016

Speech inversion (acoustic-to-articulatory mapping) is not a trivial problem, despite the importance, due to the highly non-linear and non-unique nature. This study aimed to investigate the performance of Deep Neural Network (DNN) compared to that of traditional Artificial Neural Network (ANN) to address the problem. The Wisconsin X-ray Microbeam Database was employed and the acoustic signal and articulatory pellet information were the input and output in the models. Results showed that the performance of ANN deteriorated as the number of hidden layers increased. In contrast, DNN showed lower and more stable RMS even up to 10 deep hidden layers, suggesting that DNN is capable of learning acoustic-articulatory inversion mapping more efficiently than ANN.

• Phonetics and Speech Sciences
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• v.9 no.2
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• pp.111-118
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• 2017

This study compares speech rate, articulatory rate, and pause between the children with mild and moderate Speech Sound Disorder (SSD) who performed Sentence Repetition Tasks and the Typically Developing children (TD) of the same chronological age. The results showed that three groups are categorized in terms of speaking rate and articulatory rate. There is no difference between the two groups with SSD children, namely between the mild and moderate groups. However, there is a significant difference in their rate of speech and the articulatory rate between the two groups, such that the two groups with SSD are significantly slower than the TD group. The results also showed that there are no significant difference in the length and frequency of pause between the moderate group and the mild group. However, there is a substantial difference between them and the TD group. This study, provided the basic data for evaluating the speech rate of the children and implies that there are limitations in speech rate among the children with SSD.