11. The method of building class-specific cluster systems as recited in claim 9, wherein the step of clustering includes the step of clustering by a bottom-up method.
11. The method of building class-specific cluster systems as recited in claim 9, wherein the step of clustering includes the step of clustering by a bottom-up method. 12. The method of building class-specific cluster systems as recited in claim 11, wherein the step of clustering by the bottom-up method includes measuring a distance between acoustic features between speakers by a Gaussian likelihood.