13. The system of claim 12 , wherein the calculating is performed based at least in part on a transformation from a second group of speech segments having the second speaking style to a first group of speech segments having the desired speaking style, wherein the second group of speech segments comprises the second speech segment, wherein the first and second groups of speech segments are associated with a same phonetic context.
13. The system of claim 12 , wherein the calculating is performed based at least in part on a transformation from a second group of speech segments having the second speaking style to a first group of speech segments having the desired speaking style, wherein the second group of speech segments comprises the second speech segment, wherein the first and second groups of speech segments are associated with a same phonetic context. 14. The system of claim 13 , wherein the first group of speech segments is represented by a first statistical model and the second group of speech segments is represented by a second statistical model, and wherein calculating the value comprises: using the transformation to transform the second statistical model to obtain a transformed statistical model; and calculating the value as a distance between the transformed second statistical model and the first statistical model.