Perceptual characteristics of broken and drop tones in Vietnamese

Abstract

Perceptual characteristics of broken and drop tones in the Vietnamese language are studied. A broken tone syllable has a glottal constriction at the middle part, while a drop tone syllable has a glottal stop at the end and has a short length. In this study, four experiments were conducted. First, expanding from our previous research, the power control for the broken tone was evaluated using several power patterns and its effectiveness was reconfirmed. The power dip pattern makes the synthetic sound of the broken tone highly intelligible. Second, the similarity between the drop tone and the first half of the broken tone were studied. Experimental results showed that they are comparable, i.e., the first half of the broken tone can be replaced by the drop tone, and the first half of the broken tone can be perceived as a drop tone. In the third and fourth experiments, the final parts of drop and broken tones were examined using different fundamental frequency (F0) patterns. As a result, we found that the drop tone has a perceptual threshold with an F0 slope, while F0 of the final part of the broken tone has a minor effect on its perception.