9. A system comprising: a processor; and a computer-readable storage medium having instructions stored which, when executed by the processor, cause the processor to perform operations comprising: analyzing acoustic features of a received audio signal from a communication device; identifying a repeating pattern of meta-data associated with the acoustic features, wherein the repeating pattern of meta-data comprises a speed of a caller associated with the communication device; classifying a background environment of the caller based on the acoustic features and the repeating pattern of meta-data, to yield a background environment classification; selecting an acoustic model matched to the background environment classification from a plurality of acoustic models; and performing speech recognition on the received audio signal using the acoustic model.
9. A system comprising: a processor; and a computer-readable storage medium having instructions stored which, when executed by the processor, cause the processor to perform operations comprising: analyzing acoustic features of a received audio signal from a communication device; identifying a repeating pattern of meta-data associated with the acoustic features, wherein the repeating pattern of meta-data comprises a speed of a caller associated with the communication device; classifying a background environment of the caller based on the acoustic features and the repeating pattern of meta-data, to yield a background environment classification; selecting an acoustic model matched to the background environment classification from a plurality of acoustic models; and performing speech recognition on the received audio signal using the acoustic model. 14. The system of claim 9 , wherein the meta-data comprises personal information associated with the caller and comprises probabilities that the caller is in a particular background environment.