Discrimination of vowels and semivowels synthesized with an articulatory model

Abstract

In order to examine the difference between perceptual manner of vowels and semivowels which are characterized by dynamic acoustic events, an articulatory model for producing both high vowels such as [i] and [w] and the syllable [ju] was first introduced. The formant frequency movements of the syllables obtained from the model were considered to be reasonable as compared with those of natural speech sounds. The difference limens (DLs) of vowels and semivowels for the changes in an articulatory point in the model were measured by an AX discrimination test. The DLs were almost the same among four semivowels having different terminal articulation points when the initial articulation points and lip opening area were kept constant. But the DLs were significantly different among four sustained vowels having the same values as the vocal tract area functions of the semivowels at a terminal point. The implications of these results for feature detecting mechanisms in the perception of vowels and semivowels are discussed with the role of phonetic framework of listeners.