A word category estimation device (101) includes a word category model (5) formed by a probability model having a plurality of types of information items on a word category as feature elements and having information concerning the entire word category graph as at least one of the feature elements. The device (101) inputs a word category graph of a voice recognition hypothesis to be processed by a word category estimation unit (4), calculates a score for each of arcs constituting the word category graph by referencing the word category model, and outputs a word category string candidate according to the scores.
WORD CATEGORY ESTIMATION DEVICE, WORD CATEGORY ESTIMATION METHOD, VOICE RECOGNITION DEVICE, VOICE RECOGNITION METHOD, PROGRAM, AND RECORDING MEDIUM