Acoustic characteristics of highly distinguishable Cantonese entering and non-entering tones.

Cantonese has one of the most complex tone systems. Few studies have thoroughly examined or compared the acoustic properties of the full set of Cantonese tones, particularly the entering tones, compromising deeper understanding of Cantonese tone difficulties in various clinical populations. This study (1) describes a theory-driven method for acoustic analysis of tones that successfully normalized the intrinsic pitch of male and female speakers, (2) provides detailed acoustic data on distinctly enunciated Cantonese tones, (3) examines the acoustic similarities and differences between the entering and non-entering tones, and (4) compares the acoustic properties of three easily confused tone pairs. Seventeen male and female native speakers produced 1802 Cantonese tones that were correctly identified by five judges in filtered stimuli. Counter to the established notion that the entering tones are shorter versions of the three level tones, the results revealed that the entering tones have falling contours, suggesting that the entering and non-entering tones should be examined separately in research and clinical settings. The detailed description of the acoustic properties of the nine tones and the acoustic contrasts of the entering and non-entering tones and the three easily confused tone pairs provides references for future Cantonese tone studies with different populations.