1. A computer readable medium storing computer-executable instructions that, when executed, cause one or more processors to perform acts comprising: obtaining trained decision tree-tied hidden Markov Models (HMMs) for a speech corpus; estimating mean parameters of a plurality of rich context models based on the trained decision tree-tied HMMs by performing a single pass re-estimation; setting variance parameters of the plurality of rich context models equal to the variance parameters of the trained decision tree-tied HMMs to produce a plurality of refined rich context models; and generating synthesized speech for an input text based at least on some of the plurality of refined rich context models.
1. A computer readable medium storing computer-executable instructions that, when executed, cause one or more processors to perform acts comprising: obtaining trained decision tree-tied hidden Markov Models (HMMs) for a speech corpus; estimating mean parameters of a plurality of rich context models based on the trained decision tree-tied HMMs by performing a single pass re-estimation; setting variance parameters of the plurality of rich context models equal to the variance parameters of the trained decision tree-tied HMMs to produce a plurality of refined rich context models; and generating synthesized speech for an input text based at least on some of the plurality of refined rich context models. 3. The computer readable medium of claim 1 , further storing an instruction that, when executed, cause the one or more processors to perform an act comprising outputting the synthesized speech to at least one of an acoustic speaker or a data storage.