1. A machine translation method comprising: converting, using a processor, a source sentence written in a first language to language-independent information using an encoder for the first language, information for which is stored in non-volatile and volatile memory; and converting, using the processor, the language-independent information to a target sentence corresponding to the source sentence and written in a second language different from the first language using a decoder for the second language, information for which is stored in the nonvolatile and volatile memory, in response to a similarity being higher than a preset threshold, wherein the similarity is determined from a comparison between pixel values of the language-independent information of the source sentence and pixel values of the language-independent information of the target sentence; wherein the encoder for the first language is trained to output language-independent information corresponding to the target sentence in response to an input of the source sentence, using the processor, wherein the processor communicates with the nonvolatile and volatile memory via a bus.