PURPOSE: To provide a method and a device for transformation of languages which can easily obtain the proper translated sentences even if the transformation of languages fails by performing an operation to evade the cause of the failure of the transformation and therefore to perform the transformation again.

CONSTITUTION: A 1st transformation part 105 transforms the character strings of a 1st language into those of a 2nd language and also outputs the success or failure of the transformation. The result of transformation is temporarily stored in a transformed character string temporary storage part 106, and the success or failure of transformation is stored in a transformation success/failure temporary storage part 107. A transformation result deciding part 108 decides the success or failure of transformation and stores the result of the first transformation in a 2nd language temporary storage part 111 if the first transformation succeeds. If not, a 2nd transformation part 110 performs again the transformation of the 1st language based on the information inputted by an operator through a 2nd transformation information input part 109. Then the character strings of the 2nd language obtained from the second transformation are temporarily stored in the part 111.