Voiceless Nasal Sounds in Three Tibeto-Burman Languages

Voiceless Nasal Sounds in Three Tibeto-Burman Languages : This paper focuses on two types of voiceless nasal sounds in Xumi, a Tibeto-Burman language: (1) the voiceless aspirated nasals /m̥/ [m̥h̃] and /n̥/ [n̥h̃]; and (2) the voiceless nasal glottal fricative [h̃]. We provide a synchronic description of these two types of sounds, and explore their similarities and differences. Xumi voiceless nasal consonants are described with reference to the voiceless nasal consonants /m̥/ and /n̥/ in Burmese and Kham Tibetan, because Burmese voiceless nasals are the best described type of voiceless nasals, and are therefore used as a reference point for comparison; whereas voiceless nasals in Kham Tibetan, which is in close contact with Xumi, represent a characteristic regional feature. The synchronic description is based on acoustic and aerodynamic measurements (the total duration of the target phonemes, the duration of the voiced period during the target phonemes, mean nasal and oral flow). Our study (i) contributes to a better understanding of voiceless nasals as a type of sound; (ii) provides a first-ever instrumental description (acoustic and aerodynamic) of the voiceless nasal glottal fricative [h̃], as attested in a number of Tibeto-Burman languages of Southwest China; and (iii) suggests a possible phonetic basis for the observed dialectal and diachronic variation between voiceless nasals and [h̃] in some Tibeto-Burman languages.

无辅音鼻音在三种藏缅语中的研究：本文专注于对西米语（一种藏缅语）中的两种无辅音鼻音进行探讨：（1）无爆破音鼻音/m̥/ [m̥h̃] 和 /n̥/ [n̥h̃]；（2）无辅音声门摩擦音[h̃]。我们对这两种音素的共时性描述进行了阐述，并探究了它们的相似之处与差异。西米语的无辅音鼻音描述参考了缅甸语和康藏语中的无辅音鼻音/m̥/ 和 /n̥/，因为缅甸语的无辅音鼻音描述得最为详尽，故用作比较的参照点；而康藏语的无辅音鼻音，与西米语紧密相邻，体现了独特的地域特色。共时性描述基于声学和空气动力学测量（目标音素的总体时长、目标音素中发音时期的时长、平均鼻音和口腔气流）。本研究（i）有助于加深对无辅音鼻音作为一种音素类型的理解；（ii）首次提供了无辅音声门摩擦音[h̃]（如在中国西南部的一些藏缅语中所示）的仪器描述（声学和空气动力学）；（iii）为一些藏缅语中无辅音鼻音与[h̃]之间观察到的方言和历时变化提供了一个可能的语音基础。