1. A system for processing natural language utterances where recognized words of the natural language utterances alone are insufficient to completely determine one or more commands or requests, the system including one or more processors executing one or more computer program modules which, when executed, cause the one or more processors to: generate a context stack comprising context information that corresponds to a plurality of prior utterances; receive a natural language utterance associated with a command or request; determine one or more words of the natural language utterance by performing speech recognition on the natural language utterance; and determine the command or request based on the one or more words and the context information.