Abstract: A device, to perform highly accurate sequence conversion consistent with the context, uses a t-th word string Xt of the first text and a sequence Y{circumflex over (?)}1, . . . , Y{circumflex over (?)}t?1 of first to (t?1)-th word strings of the second text, which is a conversion result of a sequence X1, . . . Xt?1 of first to (t?1)-th word strings of the first text to obtain a probability of copying a word from the t-th word string Xt or the sequence Y{circumflex over (?)}1, . . . , Y{circumflex over (?)}t?1, on the basis of the model parameters ?, and estimates information corresponding to a t-th word string Yt of the second text by copying a word from the t-th word string Xt or the sequence Y{circumflex over (?)}1, . . . , Y{circumflex over (?)}t?1 based on the probability of copying.

Abstract: Information corresponding to a t-th word string Yt of a second text, which is a conversion result of a t-th word string Xt of a first text is estimated on the basis of a model parameter ?, by using, as inputs, a t-th word string Xt of the first text and a sequence Y{circumflex over (?)}1, . . . , Y{circumflex over (?)}t-1 of first to (t?1)-th word strings of the second text, which is a conversion result of a sequence X1, . . . Xt-1 of first to (t?1)-th word strings of the first text. Here, t is an integer of two or greater.