12. The computer-readable storage media of claim 11 , wherein the method further comprises comparing the plurality of dialog responses with a plurality of logged dialog responses, wherein plurality of logged dialog responses includes a plurality of responses generated from the natural language expression.
12. The computer-readable storage media of claim 11 , wherein the method further comprises comparing the plurality of dialog responses with a plurality of logged dialog responses, wherein plurality of logged dialog responses includes a plurality of responses generated from the natural language expression. 14. The computer-readable storage media of claim 12 , wherein the method further comprises: determining whether at least one of the plurality of dialog responses matches at least one of the logged dialog responses; and labeling at least one of the two dialog hypotheses in the dialog hypothesis set corresponding to the at least one dialog response that matches the at least one logged dialog response.