• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.47-52
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• 2014

This study investigated how the degree of attention modulates English learners' perception of Korean stop contrasts. The contributions of VOT and F0 in perceiving Korean stops were examined while availability of attentional resources was manipulated using a dual-task paradigm. Results demonstrated the attentional modulation in the use of VOT, but not in F0: under less attention, the contribution of VOT to the perception of aspirated stops decreased, whereas that of lenis stops increased, which suggests more native-like performance. This implies that the role of attention in perceiving non-native contrasts might differ depending on how equivalent the acoustic and perceptual cues are between L1 and target L2 contrasts.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.117-123
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• 2014

This study investigated the intonation patterns of accentual phrase in Jeju dialect. 9 speakers (Experiment 1) and 6 speakers (Experiment 2) read a carrier sentence '__ youngah miwonghumnida' with a target accentual phrase varying its number of syllables from 1 to 8. The results showed that like Seoul dialect pattern could be the basic pattern of accentual phase in Jeju dialect even though several differences were observed in the realization of each tone: Flat staircase-like tones in L, M, and even in H were often observed, and a very small difference in F0 between intial L and +H was found in many speakers. For some of these differences, this paper tried to give an explanation still in the Intonational Phonology framework. However, introducing M tone as a lexical tone was also suggested as one possible solution. Finally, unlike Seoul dialect, most speakers showed pattern in an accentual phrase beginning with a strong consonant, i.e., aspirated and unaspirated obstruents including /h/ and /s/.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.101-108
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• 2014

This study investigates the effects of Japanese learners' Korean segmental production on pronunciation evaluation by Korean native raters. Read speech from 24 learners whose native language is Japanese are transcribed at the phonemic level, and confusion matrices are generated based on the phonemic transcriptions. The deviance from the canonical pronunciation found in the learners' speech is analyzed in terms of phoneme substitutions, vowel insertions, and consonant deletions. Each learner's pronunciation is rated impressionistically by 5 Korean native raters. The result shows that the deviance from the canonical pronunciation is strongly correlated with the pronunciation evaluation scores. Especially, the rates of phoneme substitutions and vowel insertions which are very strongly correlated with the pronunciation evaluation scores.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.37-45
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• 2014

Korean wh-questions and yes-no questions have morphologically the same structure. In speech, however, two types of questions are distinguished by prosodic difference. In this study, we examined if Korean native speakers can distinguish wh-question and yes-no questions produced by Chinese Korean leaners based on the prosodic information contained in the sentences. For this purpose, we performed perception analysis, and 15 Korean native speakers participated in the perception test. The results show that two types of interrogative sentences produced by Chinese Korean leaners were not distinguished by constant pitch contours. These results reveal that Chinese Korean leaners cannot match prosodic meaning and prosodic form. The most saliant prosodic feature used perceptually by native speakers to discriminate two types of interrogative sentences is pitch difference between the F0 pick of wh-word and boundary tone.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.101-108
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• 2014

This study investigates the relation among pitch range differences, speech rate and realization of stress. To identify the realization of the stress, vowel formants and durational differences of stressed and unstressed vowels are measured. The Korean learners were asked to read a textbook passage which includes nine sentences. The major results indicate that: (1) Korean speakers' pitch range is less than 50% of the native speakers; (2) There is a significantly negative relation between high-low pitch range and speech rate; (3) The vowel qualities and durations of the stressed and unstressed vowels are related to the speech rate. But these are not related to the high-low pitch range.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.57-62
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• 2014

The present study was performed to investigate and discuss the aerodynamic characteristics of whispered and normal speech during reading paragraph tasks. 39 normal females(18-23 yrs.) read 'Autumn' paragraph with whispered and normal phonation. Their readings were recorded and analyzed by 'Running Speech' in Phonatory Aerodynamic System(PAS) instrument. As results, during whispered speech, the total duration was longer and the numbers of inspiration were more frequently shown than normal speech. The Peak expiratory and inspiratory rate were higher in normal speech, but the expiratory and inspiratory volume were higher in whispered speech. By correlation analysis, both whispered and normal speech showed significantly high correlation between total duration and expiratory/inspiratory airflow duration; numbers of inspiration and inspiratory airflow duration; expiratory and inspiratory volume. These results show that whispered speech needs more respiratory effort but shows poorer aerodynamic efficacy during phonation than normal speech.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.33-40
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• 2014

The purpose of the study was to examine alternating motion rate and its variability in children with childhood apraxia of speech (CAS) compared to typically developing children. Six children with CAS aged 9-12 years old and 10 children who were age-matched participated in the study. This study measured tokens per second and variabilities of the rates during the production of /$p^*$ a/, /$t^*$ a/, and /$k^*$ a/. For variability measures of the rates, each participant was asked to repeat speech tasks three times and the average value of the rates and its standard deviation were obtained. The results revealed that the CAS group showed slower rate only at /$k^*$ a/ than the control group. The CAS group exhibited greater variability of AMR at all the tasks than the control group. The results suggested that variability of AMR might be a more distinctive speech feature to children with CAS than the rate of the speech task.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.23-32
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• 2014

This study presents the prosodic characteristics of 'Motherese' and 'Teacherese (child care teacher and kindergarten teacher)'. 21 mothers and 24 teachers spoke to children in the child care center or kindergarten. Children are in their 4;00-6;11. Speech and articulation rate, number of accentual phrases (APs), number of intonational phrases (IPs), pitch-related factors (f0, pitch range, f0 standard deviation), and intonation slope (mean Absolute, f0, q-tone slope) were measured. 2 groups spoke 2 sentential types (interrogative_ alternative question, declarative_ coordinated sentence) in 2 situations (one accompanied with the children, the other done without children, but pretending as if they were in front of the children). The results indicate that teachers show more noticeable prosodic characteristics than mothers do.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.165-169
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• 2014

Intelligibility of speech transmitted to listeners can significantly be degraded in noisy environments such as in auditorium and in train station due to ambient noises. Noise-masked speech signal is hard to be recognized by listeners. Among the conventional methods to improve speech intelligibility, consonant-vowel intensity ratio (CVR) approach reinforces the powers of overall consonants. However, excessively reinforced consonant is not helpful in recognition. Furthermore, only some of consonants are improved by the CVR approach. In this paper, we propose the corrective weighting (CW) approach that reinforces the powers of consonants according to syllable-type such as consonant-vowel-consonant (CVC), consonant-vowel (CV) and vowel-consonant (VC) in Korean differently, considering the level of listeners' recognition. The proposed CW approach was evaluated by the subjective test, Comparison Category Rating (CCR) test of ITU-T P.800, showed better performance, that is, 0.18 and 0.24 higher than the unprocessed CVR approach, respectively.

• Phonetics and Speech Sciences
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• v.6 no.3
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• pp.155-164
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• 2014

This paper proposes a new method to determine the recognition units for large vocabulary continuous speech recognition (LVCSR) in Korean by applying unsupervised segmentation and merging. In the proposed method, a text sentence is segmented into morphemes and position information is added to morphemes. Then submorpheme units are obtained by splitting the morpheme units through the maximization of posterior probability terms. The posterior probability terms are computed from the morpheme frequency distribution, the morpheme length distribution, and the morpheme frequency-of-frequency distribution. Finally, the recognition units are obtained by sequentially merging the submorpheme pair with the highest frequency. Computer experiments are conducted using a Korean LVCSR with a 100k word vocabulary and a trigram language model obtained by a 300 million eojeol (word phrase) corpus. The proposed method is shown to reduce the out-of-vocabulary rate to 1.8% and reduce the syllable error rate relatively by 14.0%.