47. A machine-readable non-transitory storage medium having instructions to cause a machine to perform a machine-implemented method comprising: identifying instances in a plurality of speech segments; creating feature vectors derived from a machine perception transformation of time-domain samples corresponding to the instances in the plurality of speech segments onto a feature space, wherein the machine perception transformation is correlated with human perception by using the time-domain samples retaining both amplitude and phase information of the speech segments, which were provided in sound data for a speech synthesis system; clustering the feature vectors using a similarity measure in the feature space; and replacing the clustered instances corresponding to the clustered feature vectors within a radius by a single instance, wherein the identifying instances, the creating feature vectors, the clustering feature vectors, and the replacing clustered instances are performed on a representation of speech segments, the representation being stored in a memory of a data processing system which includes a processor which performs the pruning.
47. A machine-readable non-transitory storage medium having instructions to cause a machine to perform a machine-implemented method comprising: identifying instances in a plurality of speech segments; creating feature vectors derived from a machine perception transformation of time-domain samples corresponding to the instances in the plurality of speech segments onto a feature space, wherein the machine perception transformation is correlated with human perception by using the time-domain samples retaining both amplitude and phase information of the speech segments, which were provided in sound data for a speech synthesis system; clustering the feature vectors using a similarity measure in the feature space; and replacing the clustered instances corresponding to the clustered feature vectors within a radius by a single instance, wherein the identifying instances, the creating feature vectors, the clustering feature vectors, and the replacing clustered instances are performed on a representation of speech segments, the representation being stored in a memory of a data processing system which includes a processor which performs the pruning. 52. The machine-readable medium of claim 47 wherein the cluster radius is controlled by a user.