Referential Density in Japanese: Diachronic Study

This study investigates referential density (RD) in the history of Japanese through manually annotated data and corpus analysis. Following Bickel’s (2003) RD1 (the ratio of overt argument NPs to available argument positions) and Noonan’s (2003) RD2 (the ratio of overt arguments to verbs), I introduce new indices to quantify the referential contribution of exaltation morphology (keigo). Drawing on prose texts from Old Japanese (OJ) and their contemporary Japanese (cNJ) translations, I demonstrate a diachronic increase in overt arguments (RD2) alongside a decline in honorific marking. While these changes might appear causally related, statistical testing reveals no direct correlation. As a preliminary conclusion, I hypothesise that the observed trends are discourse-driven and not structurally conditioned by morphosyntactic change.