Conventionally known is a technology that, given a word string, calculates a word score of a word at a specific position in the word string. Having been developed recently is a technology for calculating the word score using a neural network.
Also conventionally known is a training method for a neural network capable of calculating the word score. In such a conventional training method, the training apparatus, to begin with, converts each text making up a part or the entire training text corpus into a word string that includes a plurality of words by performing morphological analysis of the text. The training apparatus then selects an exemplary word to be input to the neural network, and an exemplary word to be output correspondingly to the exemplary input, from the word string. The training apparatus then actually inputs the exemplary input to the neural network, and acquires the result output from the neural network. The training apparatus then updates neural network parameters based on the difference between the selected exemplary output and the actual output result from the neural network.