10. A speech processing method, comprising: analyzing a set of contexts to determine available commands; formulating command structures corresponding to the determined available commands; statistically modeling at least portions of the command structures; receiving a natural language speech input representing at least one command; processing the speech input with respect to the statistically modeled portions of the command structures; determining, with respect to the statistically modeled portions of the command structures, if the speech input likely represents a command; if the speech input likely represents at least one command, determining a completeness and an ambiguity of the likely at least one command; if the likely at least one command is too ambiguous or incomplete for execution, prompting the speaker for further input to decrease an ambiguity or increase the completeness; if the likely at least one command is sufficiently unambiguous and complete for execution, executing the command, wherein 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.
15. The method according to claim 10 , wherein the command is targeted to one of a plurality of respective applications, while preserving a respective prior system state, wherein at a command restores one of a previously preserved system state.