گذار سازه ای در واکه های زبان ترکی گونه تبریز (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
از آنجایی که گذار سازه ای همخوان به واکه حاوی یکی از سرنخ های آکوستیکی برای تشخیص محل تولید همخوان است، بررسی میزان گذار سازه های یک واکه که همان شیب صعودی یا نزولی سازه در بافت cv است هدف اصلی پژوهش حاضر است. جهت نشان دادن مسیر تغییر مقادیر سازه های F1 و F2 هر یک از واکه های پیشین و پسین ترکی، شکل ها با نرم افزار اکسل ترسیم شد و از آنجایی که فضای سازه ها با توجه به ماهیت واکه در زنجیره گفتار تغییر قابل توجهی دارند تاثیر بافت آوایی برروی مقادیر فرکانسی سازه های F1 و F2 در ناحیه گذار مربوط به همخوان های لبی، تیغه ای و بدنه ای مورد بررسی قرار گرفت، به عبارتی با دسته بندی و تعمیم گذار سازه ها می توان پارامتری را تعیین کرد که به تشخیص محل تولید همخوان ها کمک کند. در نهایت مشخص شد گذار F1همه واکه ها به صورت صعودی است. افزایش مقدار گذار F1 واکه پس از پایان رهش همخوان های لبی، تیغه ای و بدنه ای یک سرنخ آکوستیکی برای بازبودن مجرای دهان و عدم وجود گرفتگی در دستگاه گفتار است. تحلیل های آماری برای مقایسه فرکانس سازه دوم هر یک از واکه ها در دو نقطه آغاز و مرکز گذار همخوان های لبی، تیغه ای، بدنه ای نشان داد که تنها در واکه های [o، u، a] تفاوت معناداری بین فرکانس سازه دوم در دو نقطه آغاز و مرکز گذار پس از همه همخوان های لبی، تیغه ای و بدنه ای وجود دارد و در بقیه موارد اختلاف این دو متغیر معنادار نیست.Formant Transitions of Turkish Vowels
Abstract
Acoustic correlates of consonantal place of articulation are numerous and varied. Burst information, onset spectra, and formant transition motion have all been implicated as the significant cues for consonant place of articulation within each labial, alveolar, and velar place category. The main purpose of this study was to investigate the transition rate of a vowel formant, which was the ascending or descending slope of the formant in CV syllables. Therefore, this analysis offered additional insights to the role of F2 transition at the onset and mid-points when serving as predictor variables. The results showed that F1 vowel transitions had an ascending slope. Increasing the value of F1 vowel transition after the releases of labial, alveolar, and velar consonants was an acoustic clue to the opening of the oral cavity and absence of obstruction/closure in the vocal tract. The statistical analyses demonstrated that only in the vowels [o, u, æ], there was a significant difference between the second formant frequencies at the two onset and the mid-points of the transition after all coronals, labials, and velars. The difference between these two variables was not significant in the other cases.
Keywords: Vowel, Transition , Formant , Syllable, Ascending or Descending Slope
Introduction
Azerbaijani language is mainly spoken in Azerbaijan and Iran (Johanson, 2010). After Farsi as the official language, Azerbaijani has the most (approximately 15-20 million) speakers in Iran (Crystal, 2010). Most of the speakers inhabit in four provinces of the northwestern part of Iran. In the literature, two striking features of Turkic morphology has been presented: first, its agglutinative nature (low level of fusion in Sapir's terminology), indicating the fact that there is basically one-one correspondence between grammatical categories and their exponents and second, its highly synthetic nature (high level of synthesis again by using Sapir's terminology), demonstrating the fact that a given word can contain a large number of morphemes. Furthermore, the syllable structure of Azeribaijani language is consonant-vowel-consonant (consonant). This indicates that tautosyllabic consonant clusters with sonority drop are acceptable. In Turkic languages, the stress falls on the final syllables of all parts of speech (noun, adjectives, adverbs, and verbs). Most of the derivational and inflectional suffixes carry the stress. However, some of the derivational suffixes and clitics are unstressed. When roots combine with an unstressed suffix, the stress falls on the immediately preceding syllable and stress shift may not take place. According to these stress-placement rules, we used target vowels in simple words with the cvc.cvc syllables.
Materials and Methods
Generally, the first 3 formants of vowels are the most important indicators providing information for distinguishing vowels from each other (Hagino et al., 2008). There is a close relation between the first formant frequency (F1) and articulatory and/or perceptual dimension(s) of vowel height. The second formant frequency (F2) corresponds with the place of maximal constriction during the production of vowels (Wang and Van Heuven, 2006). Measurement of formants is one of the elements of the acoustic analysis of vowels. The first two formants are most important for identifying a vowel (Raina, Chakraborty, and Velankar, 2014). A formant is a concentration of acoustic energy around a particular frequency in the speech wave and corresponds to a resonance in the vocal tract. Formants can be seen very clearly in a wideband spectrogram where they are displayed as dark bands. They are labeled as F1, F2, F3, F4, etc. starting with the lowest frequency (Gunasekar et al., 2017). F1 is primarily related to tongue height with high vowels having a low F1 frequency and low vowels having a high F1 frequency. F2 is mostly related to tongue advancement with back vowels having a low F2 frequency and front vowels having a high F2 frequency (Ludlow, Kent, and Gray, 2019). This study included 10 native Turkish speakers aged 20-45 years. They pronounced Turkish vowels following consonants like xɯr.dɑ, nɑ.xɯr, rɯ.zɑ, and sɑ.rɯ. Acoustic analysis of the WAV files was performed in the computer program Praat, Version 6.1.08 (Boersma and Weenink, 2019). Segmentation of vowels in words was carried out in a manual approach. Formant frequency analysis was conducted using the Formant Pro (Xu, 2018) available in Praat with its default standard settings (range of 5,000 Hz for 5 formants). We used International Phonetic Alphabet (IPA) symbols for Turkish sounds.
Discussion of Results and Conclusion
Coarticulation is generally defined as the influence of one phonetic segment on another segment (Marchal, 2009). It is an overlap between the articulations of neighboring phonemes. Articulators constantly move as we talk so that the shape of the vocal tract for a particular phoneme is influenced by the shapes for the phonemes that both precede and follow it (Goldstein, 2010).
Vocal tract movements produce transitions of formant frequencies. Formant transitions reflect the overall change in the shape of the vocal tract during speech production (Story and Bunton, 2010).
The study objective was to analyze F1 and F2 transitions in Turkish vowels in a consonant context with different places of articulation (labials: m, b, p, f, and v; coronals: s, z, d, t, n, and l; alveolo-palatals: ʃ, ʒ, ʣ, r, and ʦ; palatals: ɟ, c, and j; uvulars: ɣ and x. Therefore, this analysis offered additional insights into the role of F2 transition at the onset and mid-points when serving as predictor variables. Formant transitions in consonant-vowel sequences from real words were analyzed. Consonants with different places of articulation were included in the analysis. Finally, statistical analysis of T-test was performed for two similar groups by calculating the significance level of the difference between the F2 frequency values of the onset and the mid-points of the target vowels after the consonants.
The results revealed that F1 vowel transitions had an ascending slope. Increasing the value of F1 vowel transition after the releases of labial, alveolar, and velar consonants was an acoustic clue to the opening of the oral cavity and absence of obstruction/closure in the vocal tract. The statistical analyses demonstrated that only in vowels [o, u, æ], there was a significant difference between the frequencies of the second formant at the two onset and mid-points of the transition after all coronals, labials, and velars. The difference between these two variables was not significant in the other cases.
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