A signal processing method and apparatus suitable for processing input signals representative, for example, of words or other elemental units of a natural language, which signals fall into a plurality of different categories, is provided in which the category of each input signal is determined, search data dependent upon the category is stored, the search data stored in response to previous signals is searched in response to each new signal, the search performed being dependent upon the category of the new signal, and an output signal dependent upon the input signals and upon the results of the searches is provided. When natural language is processed, the output signals may thus be dependent upon the meaning of groups of input words or other elemental units and is provided in a form in which it may conveniently be further processed. An application of the invention in a computer control switching system is described enabling the operator to input switching instructions in natural language.
Control signal processing method and apparatus having natural language interfacing capabilities