7. A speech recognition system comprising: an input for receiving speech; a processor for recognizing speech using a set of one or more grammars; wherein the processor is adapted to receive a first speech input and recognize a prefix associated with a desired category in the first speech input, and wherein the processor is adapted to recognize the first speech input using a first grammar associated with the desired category when the prefix is recognized to generate an output; wherein the output is provided to a target software application associated with the grammar associated with the prefix; and wherein, for a subsequent speech input, the processor recognizes the subsequent speech input using the first grammar associated with the desired category if a subsequent prefix is not identified in the subsequent speech input; and the processor recognizes the subsequent speech input using a second grammar that is different than the first grammar if a subsequent prefix that indicates another category is recognized in the subsequent speech input.
8. The speech recognition system of claim 7 , wherein the prefix must be recognized in order to activate the first grammar to recognize the first speech input.