Speech production-physics, models and prospective applications

Summary form only given, as follows. Speech production is a complex feedback process in which hearing, perception and information processing in the nervous system and the brain are also involved. In this contribution, only the forward path of the feedback system is considered, including sound excitation, acoustic wave propagation within the speech production system and radiation from mouth and/or nostrils. The human organs which contribute to the speech production process are explained in brief. For the different categories of speech sounds, the mechanism of production is explained with respect to sound excitation and the different articulators. On the basis of proper tube models, the physics and acoustics of speech sound generation, propagation within the speech production system and radiation is discussed and analyzed. Under the assumption of plane wave propagation, discrete time equivalents of the uniform acoustic tube are used as elements for models of the speech production system. According to the different categories of speech sounds, discrete time models are derived which represent the main cavities and their interaction during the articulation process. The validity of these models is observed in the spectral domain and, provided that 3D-data are available, also in space. If synthetic speech is produced, an auditive comparison is possible in addition. To a certain extent, the estimation of the parameters of branched tube models is treated. The discrete time tube models which have been derived can be applied in almost all fields of speech processing like synthetic speech, speech analysis, speech and speaker recognition and also in speech coding.