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 translation unit configured to translate a first selected sentence in the first language into a sentence in the second language using the parallel translations; a next utterance table storage unit configured to store therein a next utterance table in which first identification information and second identification 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, and the second identification information identifying a sentence which has been previously selected as the next utterance of the sentence indicated by the first identification information from the parallel translation storage unit; an acquiring unit configured to acquire, from the parallel translation storage unit, next utterance candidates, which are sentences indicated by the second identification information which is associated with the first identification information of the first selected sentence, 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 the next utterance candidate, 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.