1. A speech processing method, comprising: receiving a speech input representing at least one of a command and a stream of data; analyzing the speech for characteristics of a command structure, and if so, entering a command mode; in a command mode, analyzing the speech input with respect to a set of at least one grammar representation, to determine an ambiguity and a completeness; based in the determined ambiguity and completeness, prompting the user in a contextually appropriate manner for further speech input, to at least one of reduce ambiguity and increase completeness; and if the speech input is sufficiently unambiguous and sufficiently complete, generating an output representing the command; and in an absence of a characteristic of a command structures: treating the speech input as one representative of data; and generating an output as a symbolic representation of the speech input, wherein the output generated representing the command is targeted to one of a plurality of respective applications while preserving a respective prior system state, wherein at least one of: after command execution, and in dependence on a result thereof, a system state is selectively restored or processing assumed by another application without restoring the prior system state; and a command restores one of a previously preserved system state.
4. The method according to claim 1 , further comprising the step of maintaining at least one data structure representing at least a status of a grammar, wherein the data structure is updated based on the speech input and a context; and the speech input, wherein the set of at least one grammar representation is generated dynamically based at least in part on available ones of a set of temporally varying available functions within the command structure.