• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.157-162
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• 2015

This study reports on the effective way of displaying dynamic formant information on F1-F2 space. Conventional ways of F1-F2 space (different name of vowel triangle or vowel rectangle) have been used for investigating vowel characteristics of a speaker or a language based on statistics of the F1 and F2 values, which were computed by spectral envelope search method. Those methods were dealing mainly with the static information of the formants, not the changes of the formant values (i.e. dynamic information). So a better way of investigating dynamic informations from the formant values of speech signal is suggested so that more convenient and detailed investigation of the dynamic changes can be achieved on F1-F2 space. Suggested method used visualization of static and dynamic information in overlapped way to be able to observe the change of the formant information easily. Finally some examples of the implemented display on some cases of the continuous vowels are shown to prove the usefulness of suggested method.

• Speech Sciences
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• v.11 no.4
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• pp.7-15
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• 2004

In this paper, we develop a vowel training assistant method using vowel formant statistics. Formant statistics were obtained from a PBW set consisting of 452 words from 8 persons. Then we calculated distance from input formants to each center of vowel formant space. Based on the distance, directions could be given to correct the speaker's manner of articulations, i.e. position of jaw and tongue.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.133-139
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• 2014

This paper describes several approaches to transform a speaker's individuality to another's individuality using frequency warping between bilingual formant frequencies on different language environments. The proposed methods are simple and intuitive voice conversion algorithms that do not use training data between different languages. The approaches find the warping function from source speaker's frequency to target speaker's frequency on formant space. The formant space comprises four representative monophthongs for each language. The warping functions can be represented by piecewise linear equations, inverse matrix. The used features are pure frequency components including magnitudes, phases, and line spectral frequencies (LSF). The experiments show that the LSF-based voice conversion methods give better performance than other methods.

• MALSORI
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• no.58
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• pp.19-34
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• 2006

The present study investigates the vowels of Bahasa Malaysia and Bahasa Indonesia in terms of the first two formant frequencies and provides a three-dimensional formant chart of vowels by plotting F1, F2, and the frequency of datapoints on 4 different scales: Hz, mel, bark, and the number of ERB. For this study, we recruited 30 male native speakers of Bahasa Malaysia and Bahasa Indonesia (15 each) which include 6 vowels (i, e, a, o, u, e) in various contexts. The three-dimensional formant chart showed geophysics of vowel space, such that mountain peaks stand in particular locations with a higher frequency of occurrence of datapoints. The geophysics of vowel space may shed lights on the perceptual structure of vowel space. The results also showed that vowels in utterance-final positions have a significantly higher F1 and a significantly lower F2 than those in utterance-medial or utterance-initial positions, which means that vowels in utterance-final positions are more back and lower in vowel space than those in utterance-medial or utterance-initial positions.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.69-72
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• 2004

In this paper, we tried to develop a vowel training assistant method using vowel formant statistics. Formant statistics were obtained from PBW set consists of 452 words from 8 persons. Then, we calculated distance from input formants to each center of vowel formant space. Based on the distance, direct ions to correct the speaker's manner of articulation, i .e. position of jaw and tongue.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.325-328
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• 2003

In this paper, we tried to develop a vowel training assistant method using vowel formant statistics. Formant statistics were obtained from PBW set consists of 452 words from 8 persons. Then, we calculated distance from input formants to each center of vowel formant space. Based on the distance, directions to correct the speaker's manner of articulation, i.e. position of jaw and tongue.

• Phonetics and Speech Sciences
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• v.1 no.3
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• pp.65-72
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• 2009

Formant values are the most important acoustic correlates of English vowels. Classical studies on English vowels reported the first three formant values measured at a single timepoint on a sustained vowel segment. However, many recent studies revealed that partial onset or offset segments with information of dynamic spectral changes may contribute to the exact identification of English vowels with an accuracy almost comparable to that by the whole vowel segment or word. The purpose of this study was to examine formant trajectories of nine English vowels collected by Hillenbrand et al.(1995). Acoustic analysis was systematically made by a Praat script at six equidistant timepoints over the vowel segment. Results showed that the first formant trajectories played an important role in distinguishing each vowel within the front- or back-vowel groups. The second formant trajectories of the back vowels varied more drastically than those of the front vowels. The third formant value was similar except the high vowel /i/. From the vowel space on F1 by F2 axes, the formant trajectories of each vowel clearly showed a transition toward the locus of the following consonant /d/. Other acoustic data revealed that there were some vowel inherent duration or pitch values. From this study we can conclude that the dynamic spectral changes are very important in specifying acoustic characteristics of the English vowels. Further studies on vowels and diphthongs in different contexts are desirable.

• Phonetics and Speech Sciences
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• v.5 no.2
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• pp.53-58
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• 2013

The purpose of this study is to compare the first two vowel formants of the stressed and unstressed English vowels produced by ten young males (in their twenties and thirties) and ten old males (in their forties or fifties) from the Buckeye Corpus of Conversational Speech. The results indicate that the stressed and unstressed vowels, /i/ and $/{\ae}/$ in particular, from the two groups are different in their formant frequencies. In addition, the vowel space of the unstressed vowels is somewhat smaller than that of the stressed vowels. Specifically, the range of the second formant of the unstressed vowels and that of the first formant of the unstressed front vowels were compressed. The findings from this study can be applied to the pronunciation training for the Korean learners of English vowels. We propose that teachers of English pay attention to the stress patterns of English vowels as well as their formant frequencies.

• Phonetics and Speech Sciences
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• v.9 no.1
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• pp.49-53
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• 2017

Formant frequencies depend on the position of tongue, the shape of lips, and larynx. In the auditory system, the external ear canal is an open-end resonator, which can modify the voice characteristics. This study investigates the effect of the real ear on formant frequencies. Fifteen subjects ranging from 22 to 30 years of age participated in the study. This study employed three corner vowels: the low central vowel /a/, the high front vowel /i/, and the high back vowel /u/. For this study, the voice of a well-educated undergraduate who majored in speech-language pathology, was recorded with a high performance condenser microphone placed in the upper pinna and in the ear canal. Paired t-test showed that there were significant difference in the formant frequencies of F1, F2, F3, and F4 between the free field and the real ear. For /a/, all formant frequencies decreased significantly in the real ear. For /i/, F2 increased and F3 and F4 decreased. For /u/, F1 and F2 increased, but F3 and F4 decreased. It seems that these voice modifications in the real ear contribute to interpreting voice quality and understanding speech, timbre, and individual characteristics, which are influenced by the shape of the outer ear and external ear canal in such a way that formant frequencies become centralized in the vowel space.

• Phonetics and Speech Sciences
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• v.1 no.4
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• pp.3-9
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• 2009

Acoustically English vowels are defined primarily by formant values. The measurements of the values have been usually made at a few time points of the vowel segment despite the fact that the majority of English vowel formants vary dynamically throughout the segment. This study attempts to collect acoustic data of the nine English vowels published by Hillenbrand et al. (1995) online and to examine the acoustic features of the English vowels for phoneticians and English teachers. The author used Praat to obtain the data systematically at six equidistant timepoints over the vowel segment. Obvious errors were corrected based on the spectrographic display of each vowel. Results show that the first two formant trajectories are important to separate the nine vowels within the front- or back-vowel groups. The third formant trajectories appear comparable except those of the high vowels. Second, the back vowels leave longer traces on the vowel space toward the locus of the following consonant /d/. Third, each vowel has inherent duration, pitch, and intensity patterns. The results match the findings of Yang (2009). From the results, the author concludes that dynamic spectral changes are important in specifying acoustic characteristics of English vowels. Further studies on the application of the vowel trajectories to English pronunciation lessons or on perceptual experiment of synthesized vowels are desirable.