Volume 59, Issue 4

This paper reports an acoustic study of CV sequences in Italian (where C is /b, d, g, p, t, k/ and V is one of the seven Italian vowels in stressed position). It explores the effects of vowel height, consonantal voicing, and place of articulation on a number of acoustic attributes of vowels (duration, f₀, F₁), and on the duration of the preceding stop closure, VOT and RVOT (defined as the interval from C release to the acoustic vowel onset). The aim is to provide, for Italian, a comprehensive account of all the various interactions between consonantal voicing, vowel height and consonant place on the above acoustic attributes in order to propose an explanation for such effects, and to compare the present results and interpretations with previous explanations and with previous data on Italian and other languages.

Individual subjects have been found to show considerable variation in the extent to which they manifest certain temporal patterns of English in their speech. Because at least some differences across speakers appear to be related to the fact that some subjects typically talk faster/slower than others, the present investigation examined variability in temporal patterns by having subjects produce target stimuli in sentences spoken at normal and fast rates. The results from these manipulations of speaking rate generally supported previous findings related to temporal patterns as a function of ‘natural’ variations in rate of speech. That is, there was considerable variability among the 15 subjects in the normal speaking rate condition in the extent to which temporal parameters such as final-syllable vowel lengthening occurred. In addition, there was substantial variation in these parameters in the fast speaking rate condition, and some systematic changes in certain patterns also occurred as a function of the rate change. For example, vowel lengthening preceding voiced obstruents tended to decrease when subjects spoke at a fast versus a normal rate, whereas phrase-final vowel lengthening was typically greater when they spoke at a faster rate.

While the existence of the trough effect is unquestioned, its theoretical significance is unknown. A multifaceted instrumental approach – spectrographic, cineradiographic, and vocal tract modeling – was used to document the trough effect in open (V.CV) and closed (VC.V) syllable forms using a symmetrical vowel context surrounding labial stops. Collectively, the results document the trough phenomeon as a momentary deactivation of tongue and/or lip movement after V1 and continuing into the stop closure. This empirical event suggests a segment-by-segment activation pattern as opposed to a diphthongal vowel-to-vowel trajectory with an independent and superimposed consonantal gesture. Quantitative models of VCV coarticulation must incorporate the trough effect in order to more effectively capture the kinematic properties of speech.