11. The method according to claim 10 , further comprising: preparing the screen character string control table, wherein the screen character string control table comprises: the master identifier; the character string associated with the identifier within the message file that is associated with the master identifier; a translated character string, and the respective language identifiers associated with the screen character string and the translated character string; the category information associated with the character string; a first appearance positional information associated with the character string in the program product; and a second appearance positional information associated with the character string and the translated character string respectively.
11. The method according to claim 10 , further comprising: preparing the screen character string control table, wherein the screen character string control table comprises: the master identifier; the character string associated with the identifier within the message file that is associated with the master identifier; a translated character string, and the respective language identifiers associated with the screen character string and the translated character string; the category information associated with the character string; a first appearance positional information associated with the character string in the program product; and a second appearance positional information associated with the character string and the translated character string respectively. 12. The method according to claim 11 , further comprising: associating the master identifier of the character string that is included in the manual with an incorporating screen character string, in response to a command to incorporate the translated character string displayed on the program product; and updating the screen character string control table by: associating the set of the master identifiers that is associated with the incorporating screen character string, wherein the incorporating screen character string is the character string translated into another language.