Auditory accounts of temporal factors in the perception of Norwegian disyllables and speech analogs

Abstract

The first part of this study investigates temporal factors in the perception of V:C vs. VC: rhymes in Norwegian. To that aim, a listening test was performed with stimuli of the form /mV:Ce / vs. /mVC:e/with varying vowel, consonant closure and schwa duration. For a group of native speakers, boundaries in the perception of /V:/-/V/were established. Both longer consonantal closure and schwa duration appeared to cause a perceptual shortening of the vowel. These results were interpreted by appealing to Kingston & Diehl's (1994) duration ratio hypothesis, which states that the durations of a vowel and a following consonant are mutually enhancing acoustic cues. In two listening tests on speech analogs, listeners judged the duration of the first tone in tone-gap-tone sequences. Mimicking the speech stimuli, these sequences featured varying gap and second tone durations. Longer durations of these two signal parts turned out to perceptually lengthen first tone duration. The divergent results from the speech as opposed to the non-speech stimuli were explained by assuming different perceptual strategies for the two types of signals. While in speech the listeners can rely on well-established temporal patterns, such a framework is absent in the case of non-speech.