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Three Problems in the Theory of the Optional Infinitive Stage : Stage / Individual Predicates , Eventive Verbs and Finite Null-Subjects

Much of the early morphology and syntax of clause structure (until roughly age 3;0) can be described via the Optional Infinitive (OI) model (Wexler 1990, 1992, 1994), and recent versions of the theory incorporating the Unique Checking Constraint (UCC) (Wexler 1998) successfully explain variation in whether a language goes through the OI stage. The purpose of this paper is to apply the theory to three further phenomena which appear to describe early morphosyntax: