Tongue body movements in speech: Straight or curved paths?

This paper examines tongue body movements between two vowels with particular emphasis on the shape of the movement paths. Earlier work on tongue movements in speech has mostly focused on movements for consonants. The movements analyzed are from the first to the second vowel in a sequence of vowel-bilabial consonant-vowel. Native speakers of Japanese and Italian served as subjects. The linguistic material consisted of words with a long or short labial consonant. Recordings were made using a magnetometer. To assess the movement path, the movement magnitude was calculated in two ways as a straight line, the Euclidean distance, and as the actual path, obtained by summing the individual Euclidean distances between successive samples from movement onset to offset. The ratio between the path and the Euclidean distance is 1 when the movement is a straight line and greater than 1 when the path is curved. For most of the movements, the ratio was less than 1.1, thus suggesting that these movements are almost a straight line. There was no clear difference between movements during long and short labial consonants. [Work supported by NIH.]