1. A method comprising: classifying, by a computing device, speech into at least one voice cluster based on identified acoustic features of the speech, the at least one voice cluster corresponding to a text cluster and a customized language model that reflects characteristics of a speaker of the speech; determining, by the computing device, a text query based on the customized language model and one or more text strings determined based on the speech; receiving, by the computing device, search results based on the text query, each of the search results having a ranking indicating a measure of importance relative to other of the search results; and re-ranking, by the computing device, the search results based on re-scoring the search results using the text cluster.