Ф-feature agreement: the distribution of the Breton bare and prepositional infinitives with the preposition da

This article investigates the hypothesis that infinitive clauses in Breton are case-filtered. This hypothesis makes a straightforward prediction for the distribution of infinitive clauses: bare infinitives appear in positions where direct case is available to them; prepositional infinitives appear as a last resort, in positions where no case is available. In these environments, da, homophonous with a preposition, appears at the left-edge of the infinitive clause. I propose that da realizes inherent case. I show that once the paradigms of semantically motivated preposition insertion are set apart, the hypothesis shows correct for control and ECM structures, with both intervening subjects and objects, purpose clauses and their alternation paradigms, including some preposition tripling paradigms. Larger infinitive structures in narrative matrix infinitives and concessive clauses are not case-filtered. This makes Breton similar to English, where only perception and causative structures are case-filtered, whereas other infinitive structures are not (Hornstein, Martins & Nunes 2008).