Vladimir M. Barsukov
Res. Lab. of Electron., MIT, Cambridge, MA 02139
Acoustic analysis of the lateral consonant /l/ shows some extra, unexplained poles and zeros above the second formant. A vocal tract model with a bifurcation in the acoustic path from the glottis to the lips was analyzed to explain these acoustic characteristics. The mathematical model consists of a tube that contains an additional parallel acoustic path or a side branch with dimensions roughly consistent with the shape of the airways for /l/. A one-dimensional approximation was used to set up differential equations for sound pressure P and volume velocity U, appropriate boundary conditions were applied, and an analytical solution for the problem was found for various geometrical parameters. The analysis of this solution shows existence of the extra poles and zeros above the second formant for a reasonable set of parameters. [Research supported in part by a grant from NIDCD.]