1. A translation device comprising: a parallel translation storage unit configured to store therein a plurality of parallel translations and their respective IDs so as to be associated with each other, each of the parallel translations including a sentence in a first language and a sentence in a second language having an equivalent semantic content so as to be associated with each other; a next utterance table storage unit configured to store therein a next utterance table in which first identification information, second identification information, and frequency information are associated with each other, the first identification information having the ID and distinguishing between the sentence in the first language and the sentence in the second language included in the parallel translation indicated by the ID, the second identification information identifying a sentence which has been previously selected as a next utterance of the sentence indicated by the first identification information from the parallel translation storage unit; and the frequency information indicating a frequency of selection of the sentence indicated by the second identification information that is selected as the next utterance of the sentence indicated by the first identification information; a translation unit configured to translate a first selected sentence in the first language into a sentence in the second language using the parallel translations; an update unit configured to update the frequency information associated with the first identification information of a previously selected sentence and associated with the second identification information of the first selected sentence; an acquiring unit configured to acquire, from the parallel translation storage unit, within a predetermined number of ranges, next utterance candidates, which are sentences respectively indicated by a plurality of pieces of the second identification information which are associated with the first identification information of the first selected sentence in descending order of the frequency of selection indicated by the frequency information, with reference to the next utterance table; a display unit configured to display the first selected sentence, a translation result of the first selected sentence, and the next utterance candidates; and a selection receiving unit configured to receive a selection of any one of the next utterance candidates, wherein, if the selected next utterance candidate is the first language, the translation unit translates the selected next utterance candidate into the second language using the parallel translations, if the selected next utterance candidate is the second language, the translation unit translates the selected next utterance candidate into the first language using the parallel translations.