Hyo-kyung Park. 2011. A study on the foundation of modern Japanese style: Focused on ‘だ’ and ‘じゃ（ぢゃ）’ in noun sentences . Language Information . Volume 13. 5-22.
Conclusive auxiliary verbs which organize a noun sentence in modern Japanese are consisted of ‘da/de-aru/desu/de-arimasu/de-gozaimasu’, which are sentence final particles. Most of all, there are two auxiliary verbs that are comparable in usage. ‘da’ used to be a dialect derived from Kanto province since the Middle Ages, while ‘ja’ originated from Kansai province. After the standard language had been enacted, ‘da’ is now used as a standard form while ‘ja’ is considered to be a ‘博士語’ or ‘老人語’. I researched ‘da’ and ‘ja’ that can be seen in the works of various genre in the early Meiji era with the aim of clearly differentiating the two forms. In conversation, ‘da’ has been used regardless of speaker's class and gender since it has always been a spoken style. Although ‘ja’ had a feature of a colloquial style which was used in lecture notes and addresses. (Research Institute for Language & Information, Korea University)
Key words: the Meiji Era, Noun Sentence, Spoken Language, Colloquial Style, Conclusive Auxiliary Verb, ‘da’ ‘ja’ Sentence Final Particle, Stylistic Study