18. The system of claim 17 , wherein the speech recognition engine is configured to dynamically constrain a vocabulary of words associated with a virtual dictation grammar to include one or more decoy words for out-of-vocabulary words based on one or more prior utterances that were successfully transcribed by the speech recognition engine.
17. A system for knowledge-enhanced speech recognition, comprising: a context stack configured to store one or more expected contexts associated with a natural language utterance; and a knowledge-enhanced speech recognition engine, wherein the knowledge-enhanced speech recognition engine includes one or more processors configured to: access the one or more expected contexts stored in the context stack in response to one or more active grammars in a context description grammar failing to completely match information associated with the natural language utterance; compare the information associated with the natural language utterance to one or more context specific matchers to determine a most likely context associated with the natural language utterance from the one or more expected contexts stored in the context stack; and use one or more grammar expression entries in the context description grammar to generate a command or request associated with the most likely context, wherein the information compared to the one or more context specific matchers includes phonetic information associated with the natural language utterance or text combinations from a transcription associated with the natural language utterance.