Formal mismatches and functional advantage in syntactic change The case of Old and Middle Russian non-verbal predicates

This paper relies on the idea that syntactic change stems from linguistic factors that are different in nature and, consequently, trigger different results. Specifically, I distinguish the causes, processes and results related to two different kinds of syntactic change, a 'formal' type of change vs. a 'functional' one. The hypotheses pursued here are the following: (i) Mismatches between the formal features a learner has acquired and certain data she receives during the language acquisition period lead to a syntactic change type, which restructures completely the syntactic derivation involved; (ii) The advantage of parsing one variant over parsing another triggers a different kind of change, namely one that affects specific instances or uses / registers of the crucial syntactic structure. To illustrate this, I analyze the role of functional advantage and formal changes in the historical development of the case system of Russian non-verbal predication.