Nowadays, communication and interaction between humans and autonomous robot systems suffer from the fact that the "language" that robots understand is highly formalized, and perceived ineffective and unnatural by humans. By contrast, human natural language may be considered a proof that efficient communication is possible - even if grammar and syntactic formalisms are reduced down to the level of keyword speech. In this book, the author develops an autonomous robot system, completely based on nonlinear dynamics theory, that is capable of understanding and reacting on human keyword speech input in a natural and intuitive way. Thanks to the unified design entirely based on dynamical systems the developed system is able to perform well and stable in natural and dynamic environments.