Non-Canonical Agreement in Early Grammars

Abstract

Children acquiring a diverse range of unrelated languages commonly go through a stage, typically between the ages of 2 and 3, where they use bare, infinitival or default forms instead of the agreeing forms required in adult grammar. Whether such under-agreement errors reflect non-adult syntax for agreement or incomplete morphological knowledge has been a topic of debate for decades (Brown 1973, Radford 1990, Rizzi 1994, Wexler, 1998, a.o.). These errors are interesting developmentally, since children otherwise make few grammatical errors, and theoretically, given the central role of agreement in understanding the combinatorial mechanisms of natural language.

In this paper, we approach this classic developmental problem from a new angle, by examining the acquisition of ‘non-canonical’ agreement constructions, where a non-standard element occupies the subject position, and agreement is with a postverbal nominal. Such constructions are generally thought to be syntactically more complex than canonical sentences, in that they involve at least two dependencies—one that is responsible for subject movement, and a second that is responsible for the verbal morphology. In these environments, we find a striking reemergence of agreement problems, now in a population who otherwise command the relevant morphology and use it in adult-like ways in canonical contexts. Two elicited repetition studies found that children (ages 3;0–5;11) routinely produced singular agreement with plural associates in non-canonical constructions. We take this over-production of singular to reflect a ‘late’ under-agreement stage, where children default to singular morphology as a result of failing to agree. Indirectly, these results support syntactic explanations of toddlers’ under-agreement and illustrate how the protracted acquisition of agreement tracks syntactic complexity.