1. A communication supporting apparatus, comprising: a supplemental example storing unit that stores a source language interpretation which is an interpretation of a semantic content of a source language sentence to be translated, and a supplemental example sentence, in association with each other, the supplemental example sentence being an example of a sentence for supplementing an intention of a user that is not expressed in the source language sentence and being different from the source language sentence; an input accepting unit that accepts the source language sentence input by a user; an analyzing unit that analyzes the semantic content of the source language sentence and outputs the source language interpretation; a search unit that searches for the supplemental example sentence associated with the source language interpretation from the supplemental example storing unit; and a translation unit that translates the source language sentence and the supplemental example sentence into a target language; a personal information storing unit that stores personal information of a user including information in which contents to be spoken are associated with a level of importance indicating a level of interest of the user to the contents to be spoken; a dialog history storing unit that stores a history of dialog spoken by the user; a recognizing unit that recognizes a state of use that is information showing a state in which the user has a dialog; and a selecting unit that selects a supplemental example sentence based on at least one of the level of importance included in the personal information and the history of dialog, wherein the supplemental example storing unit stores the state of use, the source language interpretation and the supplemental example sentences in association with each other; the search unit searches for a supplemental example sentence, which is associated with the source language interpretation and the state of use, from the supplemental example storing unit; and the translation unit translates the selected supplemental example sentence.