University of Ottawa

Is there any evidence for intonational tones in Southern Vietnamese?

Investigation of Vietnamese intonation has largely focused on the phonetic properties that distinguish communicative and expressive functions. While some work has argued that it is the overall pitch register of sentences that matters (Trần, 1967; Hoàng, 1985), most research concludes that there is a combination of pitch, intensity, voice quality and duration cues (Đỗ et al., 1998; Nguyễn and Boulakia, 1999; Michaud, 2005; Vũ et al., 2006). More controlled studies have recently shown that there is substantial inter-speaker variation (Brunelle et al., 2012) and that intonation on short utterances can obscure lexical tone targets, some tones being more affected than others (Hạ, 2010; Hạ and Grice, 2010; Hạ, 2012).
A question that remains unresolved is the extent to which the intonation of Vietnamese can be formalized in terms of intonational tones. In this presentation, I will bring evidence from laboratory recordings and from a corpus of spontaneous conversations that there are no grammaticalized intonational tones in Southern Vietnamese. I will focus on two types of constituents: the word and the intonational phrase (at this point, evidence in favor of intermediate constituents such as the accentual phrase is still lacking).
I will first show that there is no evidence that Southern Vietnamese words bear lexical stress (contra Ingram and Nguyễn, 2006; Nguyễn and Ingram, 2007b; a) or that there are pitch-accents associated to prosodic word edges. I will also argue that while duration and pitch can be used for marking corrective and contrastive focus (without post-focal compression), these properties cannot be easily captured in terms of focal pitch-accents. By looking at a few thousand intonational phrases delimited by phrase-final lengthening – mostly root clauses and syntactic adjuncts – I will then propose that although sentence types have marginally different intonational properties (for instance, interrogative sentences end slightly higher than declaratives), there is too much overlap between types to posit phonologized boundary tones (ι-level T%). Furthermore, intonational differences are commonly overridden by the use of sentence-final particles, and expressive functions often blur sentence type cues.
Put together, these results point towards a prosodic system in which the heavy use of lexical tone leaves little room for grammaticalized intonational targets (pitch-accents and boundary tones). Southern Vietnamese prosodic phrasing thus seems mostly organized around durational effects, and its information structure and communicative functions largely rely on syntactic devices.