1. A method for providing a natural language voice user interface in an integrated voice navigation services environment, comprising: receiving a natural language utterance at an input device coupled to a navigation device, wherein the natural language utterance relates to a navigation context; generating one or more preliminary interpretations of the natural language utterance using a speech recognition engine associated with the navigation device, wherein the speech recognition engine uses a dynamic recognition grammar to generate the one or more preliminary interpretations of the natural language utterance; analyzing, with a conversational language processor on the navigation device, the one or more preliminary interpretations using shared knowledge and information associated with the navigation context to determine a probable interpretation of the natural language utterance in the navigation context; and executing, on the navigation device, a navigation agent associated with the navigation context to process the probable interpretation of the natural language utterance, wherein executing the navigation agent to process the probable interpretation of the natural language utterance includes: identifying, by the navigation agent executing on the navigation device, one or more requests in the natural language utterance that relate to the navigation context from the probable interpretation of the natural language utterance; and resolving, by the navigation agent executing on the navigation device, the one or more requests using information associated with a plurality of information sources, which include at least a navigation-specific information source.