19. The method of generating the record sentence of claim 18 , wherein the generating of the record sentence by combining the selected unseen unit with the speech synthesis information comprises: generating a first candidate record sentence by combining the selected unseen unit with the speech synthesis information; and generating a second candidate record sentence by performing at least one of word replacement, word addition, content word replacement, content word addition, and/or sentence structure modification.
19. The method of generating the record sentence of claim 18 , wherein the generating of the record sentence by combining the selected unseen unit with the speech synthesis information comprises: generating a first candidate record sentence by combining the selected unseen unit with the speech synthesis information; and generating a second candidate record sentence by performing at least one of word replacement, word addition, content word replacement, content word addition, and/or sentence structure modification. 21. The method of generating the record sentence of claim 19 , wherein the generating of the record sentence by combining the selected unseen unit with the speech synthesis information comprises: generating a weight for the generated second candidate record sentence; and generating a new second candidate record sentence by performing word replacement when the generated sentence weight of the second candidate record sentence is less than a predetermined threshold.