This paper explores the claim that the shape of the onset spectrum provides invariant acoustic properties for stop place of articulation, but for French stop consonants. To this end, we carried out an acoustic analysis of 750 burst stimuli extracted from natural speech. Results showed that, contrary to the invariance theory, the global form of the spectrum is not invariant (i.e. context-independent). The acoustic properties residing in this gross shape must be extracted and exploited according to the vowel nature. In order to distinguish the palatovelars from the labials and the dentals, we implemented a contextual method which extracts the compactness property. In 94% of the time, our method appropriately discriminated between the two stop categories.
Bibliographic reference. Djezzar, Linda (1995): "Some new considerations about the spectral form of French stop bursts", In EUROSPEECH-1995, 1389-1392.