Perceptual Role of Duration Feature (Non-Distinctive in Russian) in Vowel Discrimination

It was found out that allophones of vowel phonemes /i/ and /e/, surrounded by palatalized consonants, differed significantly in their duration, though their openness – the major articulator correlate of inherent vowel duration (IVD) – was practically the same. It is hypothesized that duration contrast between [i] and [e] is controlled by speakers of Russian to set off the lack of spectral distinction. In this study we try to obtain direct evidence of the perceptual role of IVD in vowel discrimination. Firstly, an experiment with synthetic vowels, covering the range from [i] to [e], was carried out to determine phonetically ambiguous stimulus. Secondly, the ambiguous stimuli of different durations were introduced into natural words, forming minimal pairs. Subjects identified the words presented. It was discovered that percentage of [i] responses was inversely proportional to stimulus duration.