Factor analysis of tongue shapes

Tracings from x rays were made of the shape of the tongue in nine vowels as spoken by five speakers of General American. The midline of the tongue on each tracing was specified in terms of twelve numbers (two orthogonal measurements for each of six defined points). The resulting 9×5×12 matrix was analyzed by the PARAFAC procedure (Harshman, this meeting). The data indicate the extent to which the midline of the tongue can be described in terms of a small number of factors. The paper will discuss the relation between these factors and the following physiological parameters: (1) jaw opening; (2) forward pull of the posterior genioglossus muscle on the tongue root (and hence raising of the body of the tongue) as opposed to backward pull of the glossopharyngeus muscle; (3) upward and backward pull of the styloglossus muscle; (4) downward pull of the hyoglossus muscle; and (5) actions of the intrinsic muslces that control the bunching of the tongue.