1. A method for processing speech, comprising: semantically parsing a received natural language speech input with respect to a plurality of predetermined command grammars in an automated speech processing system; determining with at least one automated processor: if the parsed natural language speech input unambiguously corresponds to a command and comprises information that permits context-dependent statistically reliable processing with respect to completeness, then processing the command and exiting said determining; if the received natural language speech input ambiguously corresponds to a single command or does not comprise information that permits context-dependent statistically reliable processing with respect to completeness, then prompting a user for further natural language speech input to reduce ambiguity or increase completeness, in dependence on a relationship of previously received natural language speech input and at least one command grammar of the plurality of predetermined command grammars, reparsing the further natural language speech input in conjunction with previously parsed natural language speech input, and iterating said determining; and if an abort, fail or cancel condition is present in the natural language speech input; generating a signal by the at least one automated processor in dependence on said determining.