analyzing text that is to be subjected to text-to-speech conversion to obtain text with descriptive prosody annotation;

performing clustering for samples in the obtained text through the use of a decision tree, wherein clustering comprises combining two branches of the decision tree for clustering samples if the two branches are similar for further clustering;

generating a Gaussian Mixture Model for each cluster to determine the distance between the sample and the corresponding Gaussian Mixture Model;

using electronic logic circuitry to identify a sample according to the distance; and

transforming the identified sample into synthesized speech.