11. The apparatus as claimed in claim 10 , wherein the voice information comprises pronunciation information on text converted through voice recognition on the uttered voice.
12. The apparatus as claimed in claim 11 , wherein the controller is configured to compare a reliability value for each of the plurality of similar words and a critical value assigned to each of the similar words and to set a similar word having a reliability value higher than the critical value assigned to each of the similar words as the target word.