Japanese subject markers in linguistic change: A quantitative analysis of data spanning 90 years and its theoretical implications

Based on a statistical analysis of a corpus data from the period of 1915-2005, this article discusses two variants for a subject marker in Japanese, and argues that it is a case of linguistic change in progress. While representing effects of three linguistic factors on the use of the variants, the chronological observation of each factor revealed that this phenomenon demonstrates the Constant Rate Effect. The quantitative data also provides firm evidence for effects of other independent diachronic changes on the current phenomenon, pushing the change further by shrinking the linguistic environment for the dying-out variant. Dissecting the relationship between those diachronic changes and the current phenomenon in a quantitative manner, the findings of the study reveal that the two competing hypotheses in theoretical syntax properly capture the essential syntactic properties of the phenomenon in the contemporary Japanese and the discrepancy of the two accounts is attributable to their data reflecting a different stage of its ongoing change.