5. The symbol insertion apparatus according to claim 1 , wherein for the symbol insertion likelihood obtained for the word sequence by a certain symbol insertion model, if the symbol insertion likelihood weighted according to the similarity between the speaking style feature of the word sequence and the plurality of speaking style feature models and the relevance between the symbol insertion model and the plurality of speaking style feature models is defined as symbol insertion likelihood for different models, the symbol insertion evaluation unit calculates, for each symbol to be inserted, a total of a predetermined number of the symbol insertion likelihood for different models selected from a plurality of the symbol insertion likelihood for different models which are obtained for the plurality of symbol insertion models, and evaluates the symbol with the largest total as an insertion symbol.
1. A symbol insertion apparatus for inserting a symbol in a word sequence transcribing voice information comprising: a symbol insertion likelihood calculation unit that obtains a symbol insertion likelihood of the word sequence for each of a plurality of symbol insertion models, the plurality of symbol insertion models being supplied for the word sequence to insert the symbol in for each speaking style feature; a speaking style feature similarity calculation unit that obtains a similarity between the speaking style feature of the word sequence and a plurality of speaking style feature models; and a symbol insertion evaluation unit, implemented by a processor, that weights the symbol insertion likelihood obtained for the word sequence for each of the plurality of symbol insertion models according to the similarly between the speaking style feature of the word sequence and the plurality of speaking style feature models and a relevance between the symbol insertion model and the speaking style feature model, and perform symbol insertion evaluation to the word sequence.