Effect of rate on the acoustical characteristics of Cantonese vowels

Abstract

This study investigated the effect of speech rate on the acoustical characteristics of Cantonese vowels in terms of formant frequencies, vowel space area, and vowel articulation index. The aim was to determine (1) whether vowel space area would decrease with increasing speech rate; and (2) whether vowels would be centralized during fast speech production. Thirty healthy adult participants were randomly selected to read aloud the passage The North Wind and the Sun using three speech rates: (1) habitual (which was referred to as moderate), (2) as slowly as possible, and (3) as quickly as possible. Acoustic analysis was carried out on corner vowels /i/, /u/, and /a/ selected in the passage. Results revealed that tVSA decreased with increasing speech rate, and that the corners vowels were centralized with increasing speech rate, leading to a reduction in VAI. The results suggest a possible articulatory undershoot or coarticulation when speaking quickly.