Determination of the geometry of the human vocal tract by acoustic measurements.

The geometry of the human vocal tract from the glottis (vocal cords) to the lips is one of the determining factors in human speech production and basic to a better understanding of articulation. Measurement of the vocal‐tract geometry is difficult, especially that of its time‐dependent behavior during connected speech utterances. Practically the only tools that have been available in the past for such measurements are radiography and cineradiography. Unfortunately, radiographic measurements and their evaluation are laborious. In addition, adequate cineradiography for longer utterances poses severe problems owing to dosage limitations. Alternative methods of obtaining information on the vocal‐tract geometry have therefore always remained a desideratum. In this paper, it is shown that some of the desired vocal‐tract‐shape information can be obtained by purely acoustic measurements. Two kinds of acoustic methods are discussed in some detail: measurement of the eigenfrequencies (formants) of the vocal tract a...