11. A system for providing a natural language voice user interface, comprising: one or more physical processors programmed to execute one or more computer program instructions which, when executed, cause the one or more physical processors to: receive a natural language utterance from an input device associated with a navigation device, wherein the natural language utterance relates to navigation; determine a current location of the navigation device; select, from among a plurality of sets of location-specific grammar information, a set of location-specific grammar information based on proximity between the current location and a location associated with the set of location-specific grammar information; determine an amount of available resources for processing the natural language utterance; determine a size threshold for a recognition grammar based on the amount of available resources; generate the recognition grammar with the set of location-specific grammar information based on the size threshold such that a size of the recognition grammar does not exceed the size threshold; determine one or more interpretations of the natural language utterance based on the recognition grammar; determine, based on the one or more interpretations, a destination; and determine a route from the current location to the destination.
11. A system for providing a natural language voice user interface, comprising: one or more physical processors programmed to execute one or more computer program instructions which, when executed, cause the one or more physical processors to: receive a natural language utterance from an input device associated with a navigation device, wherein the natural language utterance relates to navigation; determine a current location of the navigation device; select, from among a plurality of sets of location-specific grammar information, a set of location-specific grammar information based on proximity between the current location and a location associated with the set of location-specific grammar information; determine an amount of available resources for processing the natural language utterance; determine a size threshold for a recognition grammar based on the amount of available resources; generate the recognition grammar with the set of location-specific grammar information based on the size threshold such that a size of the recognition grammar does not exceed the size threshold; determine one or more interpretations of the natural language utterance based on the recognition grammar; determine, based on the one or more interpretations, a destination; and determine a route from the current location to the destination. 20. The system of claim 11 , wherein the one or more physical processors are further caused to: dynamically recalculate the route in response to a managed dialogue resolving the destination; and generate directions from the current location to the resolved destination to dynamically recalculate the route.