HMM-based Speech Synthesis System (HTS) - History http://hts.sp.nitech.ac.jp/?History#z5d7dda6 >December 29, 2006 > HTS version 2.0 was finally released :-) > The new features are > * Speaker adaptation, adaptive training, and semi-tied covariance transforms are supported for multi-stream HMMs/MSD-HMMs. > * MLLRMEAN, MLLRCOV, and CMLLR-based adaptation. > * CMLLR-based adaptive training. > * Decision trees for context clustering can be used to define regression classes for adaptation. > * HMGenS can read MLLRMEAN, MLLRCOV, CMLLR, and SEMIT transforms for adaptation.