A preliminary study on nasalization and phonation

Abstract Although it is widely acknowledged that different speech processes may interact with each other, the way that nasalization affects phonation remains poorly understood. This paper explores the relationship between nasalization and phonation, by analyzing the phonetic cues of the tense/lax distinction both in nasalization and non-nasalization in the Bai language. The data for discussion is from two Bai dialects, Chengbei and Jinhua, which have a tense/lax distinction in both nasalized and non-nasalized syllables. Three phonation parameters – fundamental frequency (F0), open quotient (OQ), and speed quotient (SQ) – are extracted from EGG signals for analysis. It is found that the influence of nasalization on phonation varies with the tone contours. As for the level tones, the role of phonation manner in tone distinction is not evident in nasalization in that tense tones can be distinguished from lax tones only by pitch. However, in non-nasalization, phonation manner plays an indispensable role in tone distinction, in that the contrast between tense and lax tones are reflected not only on F0 but also on OQ and SQ. Moreover, non-nasalized tense tones are more likely to be accompanied by non-modal phonation that is characterized by a significantly higher SQ. In terms of articulatory explanation, high SQ in non-modal phonation is the result of the vibration of tightened vocal folds, and the tension of vocal folds is caused by raising the soft palate in non-nasalization. As for the falling tones, the role of phonation manner in tone distinction is more salient in nasalization than in non-nasalization in Chengbei Bai, but it is not attested in Jinhua Bai. This study shows that the interaction between nasalization and phonation in Bai can be revealed in the analysis of phonation parameters, i.e. F0, OQ, and SQ.