The effect of duration on the perception of the Cantonese diphthongs

Abstract

This research project is a perceptual evaluation of the durational property of Cantonese diphthongs. The selected diphthongs being examined are two pairs of diphthongs [ai] & [i] and [au] & [u]. It is because the quality of the two diphthongs in each pair shows close proximity in both their onset and offset steady-states, and the contrastive feature between the two diphthongs in each pair is just the temporal organization of their onset and offset steady-states. The lexical words [sai55] “嘥” & [si55] “西” and [sau55] “筲” & [su55] “收” which consist of the above diphthongs were selected as examples to study the durational relationship between the onset and offset steady-states of the two diphthongs in each pair from the perceptual aspect. Stimuli of the two pairs of diphthong sounds in which the quality of both the onset and offset steady-states being kept constant and only the duration of the onset or offset steady-state being varied were synthesized. 15 male and 15 female subjects identified the stimuli and the result showed that diphthong duration is an important perceptual cue in distinguishing the two diphthongs in each pair. Secondly, the categorical boundary between the two diphthongs in each pair is determined by the duration of the onset steady-state only. Thirdly, the duration of the onset steady-state is a more prominent cue than that of the offset steady-state in distinguishing the two diphthongs in each pair. Lastly, the position of the categorical boundary between the two diphthongs in each pair is consistent with the acoustic data concerning the duration of the onset steady-state of the diphthongs.