6. The method of claim 1 , further comprising: receiving metadata that corresponds to the spoken query, wherein classifying the spoken query into the at least one voice cluster based on the identified acoustic features of the voice signal comprises classifying the spoken query based on the metadata in addition to the identified acoustic features of the voice signal.
6. The method of claim 1 , further comprising: receiving metadata that corresponds to the spoken query, wherein classifying the spoken query into the at least one voice cluster based on the identified acoustic features of the voice signal comprises classifying the spoken query based on the metadata in addition to the identified acoustic features of the voice signal. 7. The method of claim 6 , wherein the metadata comprises a time of day when the spoken query was captured.