Cantonese vowel merger-in-progress.

This study investigates an unreported ongoing sound
change in Hong Kong Cantonese. Cantonese is
arguably the only variety of Chinese that contains
long-short contrast in its vowel system, which is
essentially a contrast in vowel quality. However,
results from a production experiment with 60 genderbalanced
native Hong Kong Cantonese speakers of
three age groups suggests that this contrast is
disappearing. Extracted from a read passage, the
bark-normalized formant values of the three pairs of
vowels with length contrast ([a]-[ɐ], [ɛ]-[e], and [ɔ]-
[o]) were compared across the three age groups and
gender using linear mixed modelling. While the
length contrast is largely retained across age groups,
the acoustic difference is diminishing, especially
among the young group. This merger-in-progress is
actualized by increasing proximity in vowel height.
All the vowel pairs seem to adopt the unidirectional
merger-by-transfer, but they are realized differently:
for [a]-[ɐ] pair, the long vowel transfers to the short
one, but the other way around for the other two pairs.