Third International Conference on Spoken Language Processing (ICSLP 94)

Yokohama, Japan
September 18-22, 1994

Perception of Central Vowel With Pre- and Post-Anchors

Masato Akagi (1), Astrid van Wieringen (2), Louis C. W. Pols (2)

(1) Japan Advanced Institute of Science and Technology, Ishikawa, Japan
(2) Institute of Phonetic Sciences/IFOTT, Univ. of Amsterdam, Amsterdam, The Netherlands

A vowel identification and a vowel matching experiment were performed to examine how preceding and following anchor signals affect central vowel perception. Previous experiments had shown that dynamical aspects of stimuli and the relation between the central vowel and the adjacent anchors may induce overshoot or extrapolation during stimulus processing. The present experiments examine the relative importance of the surrounding steady-state and the formant transitions with regard to center vowel extrapolation. Assuming that continuous phoneme sequences such as consonant-vowel-consonant (CVC) or VVV can be constructed with steady-states, transitions and vowels, four stimulus conditions are used: vowel presented in isolation (called Ref.), vowel with transitions (called A), isolated vowel surrounded by steady- states (called n), and vowel with transitions and steady-states (called Q). The central vowels were always 5-formant synthesized vowels, whereas the surrounding steady state and the transitions were either single-formant type sounds or 5-formant type sounds. The experimental results suggest that: (1) central vowel extrapolation occurs with Q-type stimuli, in both single- and 5-formant conditions, whereas averaging effects are observed with A- and II-type stimuli for some of the subjects. The overall order of the amount of overshoot is Q. > U > A > Ref. in the 5-formant condition. The most natural-sounding Q-type stimuli showed the largest amount of overshoot, and (2) the amount of overshoot with a 5-formant steady-state is larger than with a single-formant steady-state especially for the Il-type stimuli. This might be an indication that the Vowelness' of the pre- and post-anchors also contributes to the amount of overshoot. The matching results were less consistent.

Full Paper

Bibliographic reference.  Akagi, Masato / Wieringen, Astrid van / Pols, Louis C. W. (1994): "Perception of central vowel with pre- and post-anchors", In ICSLP-1994, 503-506.