PURPOSE: To reduce the burden of dictionary registration to a user by providing a means which presents information related to unstored words to the user in case of addition and update of unstored words in a dictionary where words and their keywords are stored.
CONSTITUTION: At the time of the user inputs a register sentence through a sentence input part 1, a sentence analyzing part 7 converts a character string of the sentence to a character code to detect Kanji (Chinese character), and the first Kanji is retrieved on the first conversion table of a Kanji dictionary 8. A keyword is extracted from the second conversion table by the sentence analyzing part 7. If Kanji cannot be retrieved on the first conversion table, an unregistered word flag is set. If words matched to the character string do not exist in the second conversion table, an unregister flag is set. The character string is stored as an unregistered word in a recording part 13 by a dictionary updating part 12. In this case, the dictionary updating part 12 presents information related to the unregistered word stored in the storage part 13 onto a display picture to prompt the user to register it in the dictionary 8.