1. A method of generating speech from text messages, comprising: determining a speech feature vector for a voice associated with a source of a first text message; comparing the speech feature vector to a plurality of speaker models, wherein the plurality of speaker models are unrelated to the source of the first text message; based on the comparison, selecting one of the speaker models as a preferred match for the voice; associating the selected speaker model with the source of the first text message; if the speech feature vector cannot be determined, selecting one of the speaker models as a default selection; generating speech from the text message based on the selected speaker model; and automatically generating speech from subsequent text messages received from the source of the first text message, based on the selected speaker model.