Divergence through differential frequency: The grammaticalization of the Japanese connective soredewa ‘now/then’

• Reduced and non-reduced variant forms of the Japanese connective soredewa experienced divergence.
• The reduced variants dewa and jā became specialized in pragmatic use.
• The non-reduced variants reversed their trends of change over time.
• The observed functional differentiations follow the Reducing and Autonomy Effects proposed by J. Bybee (2007).

Based on an extensive analysis of Early Modern and Modern Japanese texts, the present study illustrates how the Japanese connective soredewa and its variants underwent semantic-pragmatic changes over time. More specifically, the quantitative evidence provided in this study reveals that the reduced and non-reduced forms of soredewa progressively diverged. The reduced form became strongly associated with newer functions, while the non-reduced forms reverted to their previous uses after the reduced forms increased their presence in the language. The development of the reduced forms was found to follow the Reducing and Autonomy Effects of high token frequency proposed by Bybee (2007). These results shed new light on the functional relationships that develop between reduced and non-reduced forms during grammaticalization, a topic in need of more attention and evidence in historical pragmatics.