Perceptual parsing of acoustic consequences of velum lowering from information for vowels.

Three experiments were designed to investigate how listeners to coarticulated speech use the acoustic speech signal during a vowel to extract information about a forthcoming oral or nasal consonant. A first experiment showed that listeners use evidence of nasalization in a vowel as information for a forthcoming nasal consonant. A second and third experiment attempted to distinguish two accounts of their ability to do so. According to one account, listeners hear nasalization in the vowel as such and use it to predict that a forthcoming nasal consonant is nasal. According to a second, they perceive speech gestures and hear nasalization in the acoustic domain of a vowel as the onset of a nasal consonant. Therefore, they parse nasal information from a vowel and hear the vowel as oral. In Experiment 2, evidence in favor of the parsing hypothesis was found. Experiment 3 showed, however, that parsing is incomplete.