A Phonetic Study of the Vowel System in Taizhou Chinese

Abstract

Taizhou Chinese (TZC) is spoken in Jiangsu Province on the north bank of the Yangtze River, the boundary region of Jianghuai Mandarin and Northern Wu (Xu, 2011). Similar to most Jianghuai Mandarin and Wu dialects, TZC has a large and complex vowel system. According to the previous studies, there are oral and nasal monophthongs, an apical vowel, oral and nasal diphthongs, and triphthongs in open CV syllables. Monophthongs and diphthongs can also occur in CVS syllables closed with a syllable-final glottal stop [ʔ] or CVN syllables closed with a syllable-final velar nasal [ŋ]. Several issues related to the TZC vowel system based on the previous studies are presented as follows. (i) The transcription and description of TZC vowels do not agree among the previous studies. (ii) The vowel [i] in CV syllables may be apicalized to become [ɿ] when it follows other types of consonants in addition to the alveolar fricative [s] and affricates [ts tsʰ]. (iii) The high vowels [i y u] may involve spirantization, carrying frication noise. (iv) The degree of nasalization of the nasal vowel [ẽ] and nasal diphthongs [iẽ yẽ uẽ] is weak. (v) The syllable-final [ŋ] in CV[ŋ] syllables may be dropped. This thesis aims to carry out a phonetic investigation of the vowel system in TZC. It specifically investigates (i) the formant frequencies of monophthongs, diphthongs and triphthongs in different syllable types, (ii) the apicalization and spirantization of high vowels, and (iii) the degree of nasalization of (a) nasal vowels and nasal diphthongs in CV syllables and (b) nasalized rhymes in CV[ŋ] syllables, including the retention of the syllable-final nasal [ŋ] in such rhymes.

The study collected speech data from multiple male and female native TZC speakers for acoustic and articulatory investigation. A spectral analysis was performed using Praat to measure the frequency values of the first three formants of the TZC monophthongs, diphthongs and triphthongs. For the high vowels, the harmonics-to-noise ratio (HNR) was measured to determine the spirantization of the vowels. For the nasal vowels and diphthongs and the nasalized rhymes, (i) the difference in amplitude between the first formant and the first harmonic, i.e., A1-H1, and the difference in amplitude between the first formant and the nasal formant at 950 Hz, i.e., A1-P1, were computed to quantify the degree of nasalization, and (ii) MaxDA3, the maximum difference in the third formant amplitude between consecutive time points of the rhymes was calculated to determine the presence of a syllable-final [ŋ]. In addition, linguagrams, palatograms, and pictures of the lip shapes of vowels were obtained to determine the tongue-palate contact patterns and lip gestures during vowel articulation.

The results show that there are 23 vowels or monophthongs in total in TZC, comprising [i ɿ y u ʋ̩ ɯ e o ɚ ɑ ĩ ũ ẽ] in CV syllables, [i u e ə ɔ a] in CV[ʔ] syllables, and [i ə ɔ a] in CV[ŋ] syllables. The vowel system is large, including numerous high vowels, [i ɿ y u ɯ ĩ ũ], in CV syllables. Several notable observations regarding the high vowels are made as follows. (i) The vowel [i] is apicalized after various types of syllable-initial consonants in CV syllables. It has a small F2 value similar to that of [ɿ], and its place of articulation is apicolaminal/laminal alveolar instead of dorsal palatal. (ii) The apicalized [i] or [ɿ] in TZC is spirantized like a syllabic fricative produced with strong frication noise, particularly when it is preceded by the syllable-initial fricative/affricate or in isolation. (iii) No apicalization is observed for the vowel [ĩ] in CV syllables or [i] in CV[ʔ] and CV[ŋ] syllables. Note that the vowels [ĩ] and [i] in CV[ʔ] syllables result from the monophthongization of [iĩ] and [iɪ], respectively. (iv) The vowel [y] exhibits apicalization only in a few cases, wherein it becomes a laminal alveolar sound with optional frication noise. (v) In some words, [u] is pronounced as a rounded high back vowel without frication noise, whereas in other words, it is a syllabic approximant [ʋ̩] that involves a labiodental gesture. Last, (vi) there is an unrounded high back vowel [ɯ] in CV syllables, which is not the diphthong [ɤɯ] identified in some previous studies.

There are 31 diphthongs in total in TZC, comprising [yi ui əi iɯ ie ye ue io iɑ yɑ uɑ yũ iẽ yẽ uẽ] in CV syllables, [yu ie ye ue yə uə iɔ ia ya ua] in CV[ʔ] syllables, and [yə uə iɔ ia ya ua] in CV[ŋ] syllables. The diphthongs contain an on-glide high vowel [i], [y] or [u]. A single exception is [əi], although the onset vowel [ə] tends to be dropped. The diphthongs contain a mid or low offset vowel, except for [yi ui iɯ] which results from the drop of the medial [ə] or [ɤ] from the triphthongs [yəi uəi iɤɯ]. It follows that the three triphthongs [yəi uəi iɤɯ] described in the previous studies (i.e., CJPLC, 1998; Gu, 2001; Lu, 2003; Zhang, 1991) do not exist in TZC.

The results concerning nasalization show that (i) the nasal vowels [ĩ] and [ũ] have strong nasalization and [ẽ] tends to be denasalized; (ii) for the nasal diphthongs, [yũ] has strong nasalization and [iẽ yẽ uẽ] tend to be denasalized; (iii) no merger results from the denasalization of [ẽ iẽ yẽ uẽ] because of the spectral difference from the oral counterparts [e ie ye ue]; (iv) the nasalized rhymes [ɔŋ aŋ iɔŋ iaŋ yaŋ uaŋ] that contain a back [ɔ] or a low [a] exhibit stronger nasalization than [iŋ əŋ yəŋ uəŋ]; (v) the syllable-final [ŋ] in the nasalized rhymes may be dropped after a non-back vowel, [i] or [ə], and more often after a low vowel [a]; (vi) the nasalized rhymes have strong nasalization, regardless of whether the syllable-final [ŋ] is dropped or retained; and (vii) the drop of [ŋ] results in the emergence of additional nasal monophthongs/diphthongs in TZC.

In sum, TZC has a large vowel inventory and simple syllable structures, with vowels occurring in only three syllable types: CV, CV[ʔ] and CV[ŋ]. The TZC vowels differ not only in formant frequencies but also in frication and nasalization. This study reveals the sound changes, such as apicalization, spirantization, and denasalization, of the vowels and the drop of syllable-final [ŋ] in the nasalized rhymes. To conclude, the vowels in TZC are in the process of evolving.

Date of Award	6 May 2024
Original language	English
Awarding Institution	City University of Hong Kong
Supervisor	Wai Sum LEE (Supervisor)