Tasko Stephen M, Westbury John R
Army Audiology and Speech Center, Walter Reed Army Medical Center, Washington, DC, USA.
J Speech Lang Hear Res. 2002 Feb;45(1):127-42. doi: 10.1044/1092-4388(2002/010).
A long-held view in speech research is that utterances are built up from a series of discrete units joined together. However, it is difficult to reconcile this view with the observation that speech movement waveforms are smooth and continuous. Developing methods for reliable identification of speech movement units is necessary for describing speech motor behavior and for addressing theoretically relevant questions about its organization. We describe a simple method of parsing movement signals into a series of individual movement "strokes," where a stroke is defined as the period between two successive local minima in the speed history of an articulator point, and use that method to segment speech-related movement of marker points placed on the tongue blade, tongue dorsum, lower lip, and jaw in a group of healthy young speakers. Articulator fleshpoints could be distinguished on the basis of kinematic features (i.e., peak and boundary speed, duration and distance) of the strokes they produce. Further, tongue blade and jaw fleshpoint strokes identified to temporally overlap with acoustic events identified as alveolar fricatives could be distinguished from speech strokes in general on the basis of a number of kinematic measures. Finally, the acoustic timing of alveolar fricatives did not appear to be related to the kinematic features of strokes presumed to be related to their production in any direct way. The advantages and disadvantages of this simple approach to defining movement units are discussed.
言语研究中一个长期存在的观点是，话语是由一系列连接在一起的离散单元构成的。然而，很难将这一观点与言语运动波形是平滑且连续的这一观察结果相协调。开发可靠识别言语运动单元的方法对于描述言语运动行为以及解决有关其组织的理论相关问题而言是必要的。我们描述了一种将运动信号解析为一系列单个运动“笔画”的简单方法，其中一个笔画被定义为发音点速度历史中两个连续局部最小值之间的时间段，并使用该方法对一组健康年轻说话者舌叶、舌背、下唇和下颌上标记点的言语相关运动进行分段。发音点特征可以根据它们产生的笔画的运动学特征（即峰值和边界速度、持续时间和距离）来区分。此外，被确定与被识别为齿龈擦音的声学事件在时间上重叠的舌叶和下颌特征点笔画，基于一些运动学测量，可以与一般的言语笔画区分开来。最后，齿龈擦音的声学时间似乎与推测与其产生相关的笔画的运动学特征没有任何直接关系。本文讨论了这种定义运动单元的简单方法的优缺点。
