Speaking Rate Effects on the Speed and Extent of Articulator Movements
Studies of the effects of speaking rate on articulator kinematics have reported complex, idiosyncratic changes in movement speed and extent. With increases in speaking rate, increases in movement speed or decreases in movement extent are common, though not universal (Gay, 1981). A general principle of articulator movement control posits that movement speed and extent are directly related (Kuehn and Moll, 1976). The ratio of these two measures has been observed to vary inversely with movement duration (Ostry & Munhall, 1985). Between nominal categories of speaking rate, then, the slope of a line describing the relationship between speed and extent should change predictably. In the current work, x-ray microbeam data from 5 speakers producing a wide, and nearly continuous range of speaking rates is presented. Preliminary analyses of tongue and lip flesh-point movements for two vocalic segments reveal that, contrary to conventional wisdom, speakers can demonstrate indirect relationships between movement speed and extent. Subsequent analyses will evaluate the plausibility of the hypothesis that speakers enact patterned variations in the relationship between these two variables as they change speaking rate.