Acoustic invariance for place of articulation in stops and nasals across syllabic contexts

Abstract

In earlier ASA meetings, we presented theoretical and experimental support for the view that invariant cues for place of articulation in initial voiced stop consonants reside in the gross shape of the short-term spectrum at consonantal release. It is postulated that this concept of invariant spectral shapes is generalizable across phonetic contexts to all stop consonants and nasals. We have examined the spectral shapes for a large number of tokens of initial and final voiced and voiceless stop consonants and nasals spoken in various vowel environments by four male and two female speakers. The spectra obtained were matched to a set of templates or “windows” we developed to test quantitatively for compactness and diffuseness. Between 75% and 80% of the stop consonants were correctly classified by these templates. The failure of the remaining spectra to fit these templates may reflect limitations of the particular spectral analyses as well as the role of secondary context-dependent cues for place of articulation. The application of these procedures to nasals indicates that onsets may need to be defined in terms of changes in spectral amplitude from the nasal murmur to consonantal release. [Work supported in part by NINCDS and the John Simon Guggenheim Foundation.]