Kopyura no shutsugen hishutugen ni okeru gengo henka ni tsuite.

translation provided by researcher:

From a variationist sociolinguistic perspective, this study investigates the use/non-use of copula in Japanese, particularly in front of the phrase -to omou ‘think that’. The study employed a quantitative approach, using data from large-scale corpora, including a historical corpus, as well as results from a questionnaire survey, shedding light on how the variants have been used over time and how they are currently evaluated in the community of Japanese speakers. The results of the questionnaire survey indicate that the use of copula is positively evaluated while the non-use of copula is negatively evaluated. However, the corpus study revealed that the non-use of copula used to be the default form of the variable in Old Japanese, while the use of copula is dominant in Modern Japanese. This article discusses that the shift from the non-use to the use of copula is relevant to the change in the interpretation of the particle -to that follows the variable.