4. The system according to claim 3 , wherein the sentence determiner determines whether or not there exists a language to be translated based on languages used in the plurality of sentences and the at least one language to be hidden, and comprises an automatic translator configured to translate at least a part of the plurality of sentences into the language to be translated in response to there being the language to be translated.
4. The system according to claim 3 , wherein the sentence determiner determines whether or not there exists a language to be translated based on languages used in the plurality of sentences and the at least one language to be hidden, and comprises an automatic translator configured to translate at least a part of the plurality of sentences into the language to be translated in response to there being the language to be translated. 5. The system according to claim 4 , wherein the automatic translator adds a serial code to the translated sentence when creating the translated sentence, the serial code differentiating the translated sentence from the plurality of sentences.