1. A method for training a prosody statistic model with a raw corpus that includes a plurality of sentences with punctuation, comprising: transforming said plurality of sentences in said raw corpus into a plurality of token sequences respectively; counting frequency of each adjacent token pair occurring in said plurality of token sequences and frequency of punctuation that represents a pause occurring at associated positions of said each token pair; calculating pause probabilities at said associated positions of said each token pair, based on the frequency of each adjacent token pair and the frequency of punctuation; and constructing said prosody statistic model based on said token pairs and said pause probabilities at associated positions thereof, wherein the transforming, the counting, the calculating and the constructing, are executed by a computer.