Russian kak as a temporal conjunction: Synchronic, diachronic and typological perspective

The paper deals with the evolution of the Russian temporal conjunction kak after the 19th century. Based on data from the Russian National Corpus, the paper investigates the semantic and formal restrictions that determine the use of kak in modern Russian but that were absent from the Russian language of the 19th century. The changes that have occurred are interpreted from both semantic and grammatical points of view. Semantically, they can be attributed to the fact that after the 19th century kak lost the ability to introduce a time reference for the main situation. Grammatically, I argue that the changes are due to a shift in the degree of syntactic integration of the clause introduced by kak: from tight integration to a weaker one. The latter interpretation challenges the widespread idea that temporal clauses tend to be tightly integrated cross-linguistically.