This paper describes the result of a series of fundamental researches on a word processing system, named WORD80. Given the text consisting of Ilanguel characters, Chinese characters, English alphabets and other special characters, it can provide-ㄴo-see printout, after having processed according to the commands used to control the output format of the text. Since each Hanguel character in input text is made up of and is represented as some compoents, it uses the deterministic finite automata for the formation of Hanguel from its components. When developed at first, the WORD80 can perform Hanguel to Chinese transition character by character by character. But it was thought to be more practical to do this word by word.