• Phonetics and Speech Sciences
• /
• v.4 no.1
• /
• pp.21-28
• /
• 2012

Many previous studies reported acoustic parameters of English vowels produced by a clear speaking style. In everyday usage, we actually produce speech sounds with various speaking styles. Different styles may yield different acoustic measurements. This study attempts to examine pitch and formant trajectories of eleven English vowels produced by nine American males in order to understand acoustic variations depending on clear and conversational speaking styles. The author used Praat to obtain trajectories systematically at seven equidistant time points over the vowel segment while checking measurement validity. Results showed that pitch trajectories indicated distinct patterns depending on four speaking styles. Generally, higher pitch values were observed in the higher vowels and the pitch was higher in the clear speaking styles than that in the conversational styles. The same trend was observed in the three formant trajectories of front vowels and the first formant trajectories of back vowels. The second and third trajectories of back vowels revealed an opposite or inconsistent trend, which might be attributable to the coarticulation of the following consonant or lip rounding gestures. The author made a tentative conclusion that people tend to produce vowels to enhance pitch and formant differences to transmit their information clearly. Further perceptual studies on synthesized vowels with varying pitch and formant values are desirable to address the conclusion.

• Journal of The Korean Society of Integrative Medicine
• /
• v.7 no.4
• /
• pp.89-104
• /
• 2019

Purpose : The purpose of this study was to investigate the development of korean vowels by acoustically analyzing whether children produce Korean vowels differently according to their age and gender between ages 4 and 6. Methods : A total of 104 children aged 4~6 years (56 males and 48 females) participated in this study. The participants were classified as either 4, 5, or 6 years old. Vowel speech data was obtained by asking the subjects to pronounce meaningful words in which the vowel in question was located in the first syllable. Speech analysis was performed using the Multi-speech 3700 program. Results : Age, gender, and vowel being pronounced all had significant effects on intensity. There was significant decrease with increasing age, and the intensity was significantly higher in male children than female children. Neither age, gender, nor the vowel being produced affected the fundamental frequency. The fundamental frequency produced did not differ by age or gender. The first and second formants had considerable effect on age and vowels, significantly decreased with age, and did not have a gender difference. Conclusion : The results of this study showed that children aged 4~6 have similar anatomical structures, but that maturity of speech motor skills required to pronounce vowels was correlated with age. The results of this study can be used to evaluate children's speech and develop speech therapy programs.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.9 no.1
• /
• pp.27-31
• /
• 1998

Nasal sounds include nasalized vowels and consonants. Nasal cavity is important for the acoustics of nasal sounds. Evaluating the effects of site-specific nasal obstruction on nasal sound will help us to understand the importance of nasal geometry for the nasal sound and to foretell voice change after nasal surgery This study was designed to analyze the change of nasality and formant characteristics of nasal sound by obstructing different sites around the ostiomeatal unit(OMU). Ten adult male and female volunteers participated. The nasal formants and bandwidths of nasal consonant /n/ were checked in various conditions of nasal obstruction. The nasalance of rabbit, baby, and mama passages were compared in each conditions. Nasalance of all passages decreased when anterior portion of OMU was obstructed. Center frequency of first nasal formant(NF1) of /n/ has decreased in the order of anterior, inferior obstruction. The bandwidth of NF1 decreased in female with anterior obstruction. Anterior portion of OMU is most critical to the change of nasality and acoustics of nasal consonant. When anterior portion of OMU is obstructed, the shift of NF1 to a lower frequency and the narrowing of NF1 bandwidth are the major acoustic changes of nasal consonant /n/.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.10 no.2
• /
• pp.140-148
• /
• 1999

The use of obturator is the prosthetic rehabilitation approach for restoration of the defected maxillary shape and function for the patients with palatal defect. The obturator can change the shape of vocal tract and nasality, but few reports on the effects of the change were presented. So, the authors performed the experimental study to compare the difference between the sizes of vowel triangles produced by maxillectomized patients before and after obturator-wearing and to consider how much improvement in speech intelligibility can be expected by obturator wearing. The 8 patients who were totally maxillectomized due to palatal cancer were participated as subjects. They produced 5 vowels(/a/, /i/, /u/, /e/, /o/) before and after obturator-wearing. The formants of the vowels were analyzed by the spectrogram of CSL, and their speech intelligibility were judged by normal 8 listeners. As results, the frequency of the first and the second formant showed no significant difference between the articulation before and after wearing, but the comparison of the sizes of vowel triangles, related with the speech intelligibility, showed significant difference. The vowel triangle of the articulation after wearing was larger than that of the articulation before wearing. /i/ showed the lowest speech intelligibility score among the vowel articulation before wearing. After wearing obturators, their scores increased on the whole, especially, in /a/, but the intelligibility of /u/ decreased after wearing.

• Speech Sciences
• /
• v.2
• /
• pp.67-88
• /
• 1997

The aim of this study is to develop an assessment program of speech rehabilitation for children having some language and speech disorders. Patients of dysarthria, tonsillectomy, tonsilhypertrophy, and nasal obstruction were selected for this experimental clinical phonetic study. Formant variations ($F_1\;&\;F_2$) show pre- and post-operation differences in tonsillectomy and cleft palate patients. Nasal formants ($NF_1\;&\;NF_2$) show pre- and post-operation differences in nasal obstruction. The articulation reaction time (ART) as a parameter was used to assess Voice Onset Time(VOT). It was shown longer duration for hypokinetic dysarthria and shorter for atoxic dysarthria.. The diadochokinetic rate was measured by Visi-pitch. Lower diadochokinetic rate appeared to spastic and dysarthria in comparison with the control group. It was shown that the nasalance of tonsilhypertrophy, nasal obstruction, and cleft palate patients was seen to increase after operation. In addition, the assessment of nasality can be measured only by simple vowels such as /a/ and /i/.

• Phonetics and Speech Sciences
• /
• v.3 no.3
• /
• pp.19-26
• /
• 2011

Previous laboratory studies have shown that prosodic structures are encoded in the modulations of phonetic patterns of speech including suprasegmental as well as segmental features. Drawing on a prosodically annotated large-scale speech data from the Buckeye corpus of conversational speech of American English, the current study first evaluated the reliability of prosody annotation by a large number of ordinary listeners and later examined whether and how prosodic prominence influences the phonetic realization of multiple acoustic parameters in everyday conversational speech. The results showed that all the measures of acoustic parameters including pitch, loudness, duration, and spectral balance are increased when heard as prominent. These findings suggest that prosodic prominence enhances the phonetic characteristics of the acoustic parameters. The results also showed that the degree of phonetic enhancement vary depending on the types of the acoustic parameters. With respect to the formant structure, the findings from the present study more consistently support Sonority Expansion Hypothesis than Hyperarticulation Hypothesis, showing that the lexically stressed vowels are hyperarticulated only when hyperarticulation does not interfere with sonority expansion. Taken all into account, the present study showed that prosodic prominence modulates the phonetic realization of the acoustic parameters to the direction of the phonetic strengthening in everyday conversational speech and ordinary listeners are attentive to such phonetic variation associated with prosody in speech perception. However, the present study also showed that in everyday conversational speech there is no single dominant acoustic measure signaling prosodic prominence and listeners must attend to such small acoustic variation or integrate acoustic information from multiple acoustic parameters in prosody perception.

• The Journal of the Acoustical Society of Korea
• /
• v.31 no.6
• /
• pp.353-358
• /
• 2012

This paper describes acoustic phonetic parameters for detecting nasal place in a knowledge-based speech recognition system. Initial acoustic phonetic parameters are selected by studying nasal production mechanisms which are radiation of the sound through the nasal cavity. Nasals are produced with differing articulatory configuration which can be classified by measuring acoustic phonetic parameters such as band energy ratio, band energy differences, formants and formant differences. These acoustic phonetic parameters were tested in a classification experiment among labial nasal, alveolar nasal and velar nasal. An overall classification rate of 57.5% is obtained using the proposed acoustic phonetic parameters on the TIMIT database.

• Korean Journal of Microbiology
• /
• v.31 no.1
• /
• pp.48-53
• /
• 1993

For the purpose to improve the glucoamylase productivity of Saccharomyces diastaticus, we integrated STA 1 gene into chromosomal DNA of S. diastaticus using YIp vector. After construction of Ylp-STA by the subcloning of STAI (5.3 kb) into YIp5 vector, S. diastaticus GMT-II(a. ura3. STAJ) was transformed by Ylp-STA through homologous recombination at the chromosomal STAJ gene. So we obtained the tram formants that glucoamylase productivity was increased maximum six fold. These strains transformed by the multi-copy integration of Ylp-STA in chromosomal DNA were confirmed by Southern hybridization. And the integrated Ylp-STA was maintained stably during 30 mitotic divisions.

• Journal of the Institute of Convergence Signal Processing
• /
• v.5 no.1
• /
• pp.1-5
• /
• 2004

A new method for the estimation of pitch-frequency contour of voiced speech is presented. The method is based on the double application of Kaiser's energy operator［1］, which has the capabilities of extracting amplitude and frequency of a sinusoidal waveform. According to the modulation model, a vowel can be represented by a combination of damped sinusoids representing formants, modulated by pitch pulses. Therefore, the amplitude envelope of each of the components will give a pitch-like waveform and the pitch can be obtained by averaging the frequencies of this waveform. The first part is the same as Gopalan's approach［9］, but by substituting the LPC based spectral analysis with the second application of energy operator, the algorithm becomes very simple and can be processed on-line. Although the estimation is rather coarse, the suggested algorithm can be useful for getting a general sketch of pitch contour on-line.

• Speech Sciences
• /
• v.8 no.4
• /
• pp.171-184
• /
• 2001

American English vowels and Korean vowels were compared by the plotformant method. For American English vowels, six General American English speakers pronounced English words in the b_t environment. For Korean vowels eight Kyongsang dialect speakers and eight Seoul dialect speakers pronounced Korean words in the environments of k_t, p_t and t_t. The formant plots were obtained by plotting F1/F2 tokens of 13 American English vowels on the F1xF2 plane. In spite of personal variations the 13 vowel spaces of all six American English speakers maintained their relative positions with some overlaps. Clear distinctions were made between i-I, e-$\varepsilon$, u-$\sigma$, and o-c. The domain of c and $\alpha$ overlapped for three American English speakers, but it did not for three other speakers. The 8 Korean vowel spaces of Kyongsang dialect speakers and Seoul dialect speakers were very similar and maintained their relative positions. No distinction was made between e and $\varepsilon$. In contrast with American English e which is a neutral vowel, Korean e was a back vowel. The comparison of 13 American English vowel positions and 8 Korean Vowel positions is expected to shed some light on the errors of English vowel pronunciation of Korean learners.