1. A method comprising: training a set of multiple mixture monophone models using a set of monophone transcripts to generate a set of multiple mixture context independent models; training a set of single mixture triphone models using set of triphone transcripts to generate a set of context dependent models; and estimating parameters of the context dependent models using a data dependent maximum a posteriori (MAP) adaptation method wherein parameters of tied states of the context dependent models are derived by adapting corresponding parameters of the context independent models through MAP adaptation method using training data associated with the corresponding tied states.