An important area of AI applications is based on the development of natural interfaces which are essential to the natural utilisation of computers by people. The improvement of speech recognition and natural languages are significant drivers of this area of AI. A primary goal of AI research is the ability to talk to computers and robots in conversational human languages and for them to “understand” us as quickly as we understand each other. Further natural interface research applications include the development of multisensory devices that use physical movements to operate computers; or as we know it, virtual reality. Virtual reality encompasses the use of human/computer interfaces that enable users to experience computer simulated objects, activities, spaces and other “worlds” as if they really exist.