Volume 49, Issue 1

The goal of this experiment was to examine the perceptual effects of gestural overlap or coproduction on the first consonant in a cluster. The experiment was conducted using synthetic speech stimuli containing [b#d] and [d#b] consonant clusters in two word phrases. The stimuli were synthesized using an articulatory speech synthesizer according to the linguistic gestural model of Browman and Goldstein. The influence of the relative places of constriction in the cluster and the complexity of the presentation environment are discussed. Two asymmetries with respect to gestural overlap were found. First, assimilation was more readily perceived when C₁ was an alveolar consonant than when C₁ was bilabial. Second, a two-word context encouraged the perception of anticipatory assimilation to a greater degree than an environment in which the second word had been truncated leaving only the acoustic effects of consonantal coproduction on the vowel offset. The results are discussed in terms of the linguistic gestural model with special reference to the application of this framework to the description of assimilation, multiply articulated consonants, and secondary articulations.

While the tones of Mandarin are conveyed mainly by the F₀ contour, they also differ consistently in duration and in amplitude contour. The contribution of these factors was examined by using signal-correlated noise stimuli, in which natural speech is manipulated so that it has no F₀ or formant structure but retains its original amplitude contour and duration. Tones 2, 3 and 4 were perceptible from just the amplitude contour, even when duration was not also a cue. In two further experiments, the location of the critical information for the tones during the course of the syllable was examined by extracting small segments from each part of the original syllable. Tones 2 and 3 were often confused with each other, and segments which did not have much F₀ change were most often heard as Tonel. There were, though, also cases in which a low, unchanging pitch was heard as Tone 3, indicating a partial effect of register even in Mandarin. F₀ was positively correlated with amplitude, even when both were computed on a pitch period basis. Taken together, the results show that Mandarin tones are realized in more than just the F₀ pattern, that amplitude contours can be used by listeners as cues for tone identification, and that not every portion of the F₀ pattern unambiguously indicates the original tone.

Two experiments investigate a weakening of supralaryngeal gestures in an utterance, analogous in some ways to declination of fundamental frequency and amplitude. In one experiment, acoustic measures revealed progressive centralization of stressed /i/, /a/ and /u/ left to right in trisyllabic utterances read by Tuscan subjects. A second experiment, using speakers of a different (Northern) variety of Standard Italian, found reduction in jaw opening for stressed /a/ left to right, but generally failed to replicate a centralization of /i/. This experiment further suggested that the progressive weakening of supralaryngeal gestures is largely a phrase level rather than a word level phenomenon. Both experiments found a different, V-shaped, pattern of opening to be generally characteristic of unstressed syllables.