PURPOSE: To omit the labor and time for an operator to find out the partial expressions which are not registered yet in a dictionary and to produce an instruction to register these expressions by segmenting the information on the unregistered partial expressions in addition to the register information designated by the operator out of the basic register information and then registering these extracted information into the dictionary.

CONSTITUTION: The control parts 2a and 2b decide the instructed input information supplied from an input part. If these information are not registered in a dictionary, both parts 2a and 2b instruct an application processing part 8a to perform the translation, the KANA (Japanese syllabary)/KANJI (Chinese character) conversion, etc., and sends the header data to the part 8a. Thus the part 8a performs the prescribed processing. If those input information are registered in the dictionary, the parts 2a and 2b inform the registration control parts 3a-3i of these facts. The subsequent processings are carried out by the parts 3a-3i, and the parts 3a-3i read the registered data out of the input part. If the registered data are used for the mechanical translation, for example, the header is equivalent to a language and the output information are equal to the translation words respectively. Meanwhile a header is equal to a KANA expression and the output information are equal to the KANA-KANJI expression if the registered data are used for the KANA/KANJI conversion.