This article analyzes the frequency of three clause-level coordinating conjunctions, and , but , and or , in addition to a wide range of subordinating conjunctions across the Transhistorical Corpus of Written English (TCWE). This resource includes five genres covering seven centuries: sermons and statutes dating from the fifteenth to twenty first centuries, personal letters dating from the fifteenth to twentieth centuries, and emails and WhatsApp messages dating from the twenty-first century. The study engages with three key developments in the history of English: the increase in the inventory of subordinators between 1500 and 1700, the development of expository and non-expository registers in English between 1650 and 1990, and the increase in colloquialization moving into the Present-Day English period. It finds that there is more substantial genre-conditioned variation in relation to all three developments than has previously been acknowledged. Its results also contribute to knowledge about shifts in the generic conventions of English sermons and statutes over time, and language use within email and instant messaging, most notably a preference for causal as over because in the instant messaging sample.
Marcus et al. (Wed,) studied this question.