Representation of vowels in connected speech based on speech perception experiments

After a brief look at the perceptual characteristics of vowels and CV-syllables, a method was proposed to reduce the ambiguity of vowels in continuous speech by normalizing the co-articulation effects. The method was applied to vowels in a specific phonetic environment where great ambiguity would be likely to occur, taking as their features the first and second formant trajectories. The separability between vowel clusters was found to be significantly improved for the vowel samples. Furthermore, a vowel recognition experiment was performed being the lowest three formant trajectories extracted by the LPC analysis as the features of a vowel. Vowel recognition scores, before and after the application to these formant patterns, were compared based on the Euclidian distance from the formants of sustained vowels. As a result, a significant increase in the vowel recognition score was obtained.