1. A language model creation device, comprising: a content-specific language model storing unit configured to store a first content-specific language model representing a probability that a specific word appears in a word sequence representing a first content, and a second content-specific language model representing a probability that the specific word appears in a word sequence representing a second content; and a language model creating unit configured to execute a language model creation process of: acquiring a first probability parameter representing a probability that a content represented by a target word sequence that is at least part of an inputted word sequence, which is a word sequence included in a speech recognition hypothesis generated by execution of a speech recognition process of recognizing a word sequence corresponding to a speech and is a word sequence having been inputted, is the first content, and a second probability parameter representing a probability that the content represented by the target word sequence is the second content; and creating a language model representing a probability that the specific word appears in a word sequence corresponding to a part corresponding to the target word sequence of the speech, based on the acquired first probability parameter, the acquired second probability parameter, the stored first content-specific language model, and the stored second content-specific language model.