1. A method of converting speech to text using a hierarchy of contextual models wherein said hierarchy of contextual models is statistically smoothed into a language model, said method comprising: (a) processing text with a plurality of contextual models, wherein each one of said plurality of contextual models corresponds to a node in a hierarchy of said plurality of contextual models; (b) identifying at least one of said contextual models relating to said text; and (c) processing subsequent user spoken utterances with said identified at least one contextual model.