15. A computer-implemented system, comprising: one or more computers having: an interface to receive speech utterances encoded in audio data and a transcript having text that represents the speech utterances; a prosodic contour extractor to extract prosodic contours from the utterances; a transcript analyzer to extract attributes of text associated with the utterances; an attribute comparer to determine, for pairs of utterances from the speech utterances, distances between attributes of text associated with the pairs of utterances; a prosodic contour comparer to determine, for the pairs of utterances from the speech utterances, distances between prosodic contours for the pairs of utterances; a model generator programmed to generate a model based on the determined distances for the attributes and the prosodic contours, the model adapted to estimate a distance between a determined prosodic contour for a received utterance and a prosodic contour for a synthesized utterance when given a distance between an attribute of text associated with the received utterance and an attribute of text associated with the synthesized utterance; and a computer-readable memory device associated with the one or more computers to store the model.
15. A computer-implemented system, comprising: one or more computers having: an interface to receive speech utterances encoded in audio data and a transcript having text that represents the speech utterances; a prosodic contour extractor to extract prosodic contours from the utterances; a transcript analyzer to extract attributes of text associated with the utterances; an attribute comparer to determine, for pairs of utterances from the speech utterances, distances between attributes of text associated with the pairs of utterances; a prosodic contour comparer to determine, for the pairs of utterances from the speech utterances, distances between prosodic contours for the pairs of utterances; a model generator programmed to generate a model based on the determined distances for the attributes and the prosodic contours, the model adapted to estimate a distance between a determined prosodic contour for a received utterance and a prosodic contour for a synthesized utterance when given a distance between an attribute of text associated with the received utterance and an attribute of text associated with the synthesized utterance; and a computer-readable memory device associated with the one or more computers to store the model. 20. The system of claim 15 , wherein the system is further programmed to align the utterances in the audio data with text, from the transcripts, that represents the utterances to determine which speech utterances are associated with which text.