Abstract: To translate Japanese having no morphological distinction between singular and plural forms into English having a morphological distinction between the two, for instance, the dictionary unit includes semantic information indicative of the plural number, and the translation unit syntactically and semantically translates Japanese into English as follows: a Japanese sentence is morphologically analyzed into basic morphemes by an inflection information dictionary; lexical syntactic information of the Japanese basic morphemes are retrieved form a word/phrase dictionary; the Japanese sentence is syntactically analyzed into an intermediate structure by Japanese syntactic analysis grammar to clarify modification relationship between two words; the Japanese intermediate structure is semantically transferred into an English intermediate structure by structure transfer grammar; a concept data of a noun (e.g. "book") which includes FEATURE:NUMBER=PLURAL is formed when the noun is modified by an adjective (e.g.