Production and perception of Vietnamese short vowels

It is well known that vowels can be produced in isolation, acoustically stable, in such a way that they can be represented as points in the F1-F2-F3 space. Vietnamese language presents 13 vowels, but only 9 vowels [i, u, e, o, a, ɔ, ɛ, ɯ, ɤ] can be pronounced in isolated mode. A previous study showed that the 4 remaining vowels [ă, ɛ̆, ɔ̆, ɤ̆] have same target characteristics (F1, F2, F3) as, respectively, the vowels [a, ɛ, ɔ, ɤ] but their dynamics (the rates of CV transitions) are clearly distinct. The paper analyses the production of Vietnamese VC, including classical vowels and special vowels in terms of duration, format evolution and rate of VC transitions. Measurements show that vowel durations of [ă, ɔ̆, ɤ̆] are always shorter than the one of the corresponding vowels [a, ɔ, ɤ] and are not acoustically stable, on the one hand, and the vowel [ɛ̆] has acoustic characteristics as a diphthong. In perception tests, synthesized syllable [a-t], [ɤ-t], [ɔ-k] with changing vowel duration are recognized as [ă-t], [ɤ̆-t], [ɔ̆-k] when then duration of initial vowel [a, ɤ, ɔ] are 50%-70% shorter. It means that the vowel duration is an important parameter that allows Vietnamese distinguishing the classical vowels and special vowels in Vietnamese language.

@InternationalConference{NCC08,
  author       = {NGUYEN, V. and CARRE, R. and CASTELLI, E.},
  title        = {Production and perception of Vietnamese short vowels},
  booktitle    = {ASA},
  year         = {2008},
  url          = {/2008/NCC08},
}