[Hemispheric specialisation of language and brain rhythms].

How human language has evolved remains enigmatic. It is plausible to assume that mutual constraints of speech perception and production mechanisms shaped spoken communication. Speaking and understanding (speech) depend on performance limits of the related sensory and motor systems. Hence, the auditory apparatus evolved to understand speech as it is produced by the motor system, and the motor system such as to produce a signal that is decodable by the auditory system. Two theories attempt to bridge the functional properties of perceptual and motor language systems to account for the physical characteristics of the speech signal.