Perceptual assessment of fricative–stop coarticulation

Abstract

The perceptual dependence of stop consonants on preceding fricatives [Mann and Repp, J. Acoust. Soc. Am. 69, 548–558 (1981)] was further investigated in two experiments employing both natural and synthetic speech. These experiments consistently replicated our original finding that listeners, report velar stops following [s]. In addition, our data confirmed earlier reports that natural fricative noises (excerpted from utterances of [stx], [skx], [ℱtx], and [ℱkx]) contain cues to the following stop consonants; this was revealed in subjects’ identifications of stops from isolated fricative noises and from stimuli consisting of these noises followed by synthetic CV portions drawn from a [tx]–[kx] continuum. However, these cues in the noise portion could not account for the contextual effect of fricative identity ([ℱ] versus [s]) on stop perception (more ’’k’’ responses following [s]). Rather, this effect seems to be related to a coarticulatory influence of a preceding fricative on stop production: Subjects’ responses to excised natural CV portions (with bursts and aspiration removed) were biased towards a relatively more forward place of stop articulation when the CVs had originally been preceded by [s]; and the identification of a preceding ambiguous fricative was biased in the direction of the original fricative context in which a given CV portion had been produced. These findings support an articulatory explanation for the effect of preceding fricatives on stop consonant perception.