Tone perception in Northern and Southern Vietnamese

The experiment presented in this paper shows that Northern and Southern Vietnamese tones in isolation are identified by listeners through a small set of acoustic properties. Each of these perceptual cues is used for more than one tone, which suggests that listeners establish economical patterns of perceptual contrast. Although the two dialects under study share common identification cues, they also exhibit differences, especially with respect to the use of voice quality, which is an important cue in Northern Vietnamese but only plays a limited role in Southern Vietnamese. Results further suggest that Southern Vietnamese listeners can adjust their perception strategies to northern cues, which is expected since Northern Vietnamese is the standard national variety. Interestingly, the phonetic properties of tones (perceptual or acoustic) do not match the phonologically active tone classes of Vietnamese. Based on these results, previous models of Vietnamese tone features are challenged and a model of abstract tonal categories associated with a flexible phonetic knowledge is argued for.