A two-dimensional vocal cords model coupled with a one-dimensional unsteady flow model is presented for an analysis of phonation. The vocal cords model consists of distributed springs and dampers covered with a massive elastic membrane. The flow model includes energy loss of flow separation and reattachment. Using this analytical model the effect of the stiffness of the vocal cords on the sound quality of speech is examined. The numerical results show that as the stiffness increases, the fundamental frequency of the vocal cords' oscillation increases except around the stiffness at which the vocal cords start to oscillate without contact. In the case of very low stiffness, the vocal cords oscillate non-periodically.
