ABSTRACT

The vocal folds, together with glottal airflow, constitute a highly nonlinear self-oscillating system. It will be shown that bifurcations to subharmonic phonation, biphonation, and chaos can be observed in newborn cries, pathological voices and mammalian vocalization. It turns out that narrow-band spectrograms and pitch contours are appropriate tools to analyze these nonlinear phenomena. A simplified two-mass model is presented which allows numerical simulations of the observed phenomena. The predictions of the model are confirmed experimentally with the aid of an analog circuit, excised larynxes, and high-speed glottography.