On the Causes of Language Change: The Evolution of the Grammatical System or the Evolution of the Grammatical Forms?

Behind the history of the Slavic short, long and pronominal forms of adjectives is a radical change of the grammatical nominal system. The paper demonstrates that it is not a history of the forms but a history of the evolution of the grammatical relations: definiteness in the opposition to indefiniteness, subjectness in the opposition to attributivity, predicativity in the opposition to attributivity. The discussed problem is just a particular case of the general theoretical and methodological question of the causes of language changes: does the evolution of the system regulate the forms' evolution or do the single forms' changes result in the systems' changes.