7. 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: selecting a plurality of language models; and for each time period of a plurality of time periods: identifying a first utterance and a second utterance received during each time period, wherein the first utterance was recognized using a first language model of the plurality of language models and the second utterance was recognized using a second language model of the plurality of language models; identifying distinctions between the first utterance and the second utterance for each of the plurality of time periods, wherein the distinctions are identified by comparing phonemes between the first utterance and the second utterance; determining when a significant word usage change has occurred within the first language model and the second language model by comparing the distinctions to previously recorded distinctions; when the significant word usage change is detected, updating the plurality of language models according to the distinctions; and outputting a list of utterances with analytical information about the distinctions.
7. 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: selecting a plurality of language models; and for each time period of a plurality of time periods: identifying a first utterance and a second utterance received during each time period, wherein the first utterance was recognized using a first language model of the plurality of language models and the second utterance was recognized using a second language model of the plurality of language models; identifying distinctions between the first utterance and the second utterance for each of the plurality of time periods, wherein the distinctions are identified by comparing phonemes between the first utterance and the second utterance; determining when a significant word usage change has occurred within the first language model and the second language model by comparing the distinctions to previously recorded distinctions; when the significant word usage change is detected, updating the plurality of language models according to the distinctions; and outputting a list of utterances with analytical information about the distinctions. 11. The system of claim 7 , wherein the plurality of time periods comprises two non-overlapping months.