Using gated audiovisual speech perception to identify the temporal onset of coarticulation in production

Abstract

The goal of the present work was to develop a sensitive, non-invasive method for accurately assessing the temporal scope of coarticulation in speech production. Building on work in audiovisual speech perception (Munhall and Tohkura, 1998; Moradi et al., 2013), we used a gating paradigm and human judges to identify the temporal onset of anticipatory lip rounding in simple SVO sentences produced by five adult females. The sentences were gated based on acoustic landmarks from the midpoint of the verb through to the midpoint of the object noun. Full sentences were also included. Judges were asked to decide whether the object noun rhymed with rounded “oop” or unrounded “ack.” Results indicated an earlier correct identification of rounding in the audiovisual condition compared to the control, audio-only condition. The audiovisual judgments also provided greater temporal specificity regarding the onset of coarticulation than could obtained with acoustic measurement or with a video-based kinematic measure. Insofar as human judges appear to anticipate and even benefit from head movement in audiovisual speech tasks (Munhall et al., 2004), our method should prove especially useful for measuring the temporal extent of coarticulation in younger, more rambunctious speakers.