The Theta Misanalysis Hypothesis: Non-Target Theta Assignment and Passive Unaccusatives in L2 English Acquisition

Abstract

The distinction between two classes of intransitive verbs, unaccusatives (e.g., fall, appear) and unergatives (e.g., run, cry), has been argued to exist in L2 interlanguage grammar. This claim is supported by evidence that L2 English learners frequently produce and accept unaccusatives in passive constructions, suggesting an underlying association between NP-movement in unaccusative and passive derivations. Specifically, learners appear to misanalyze NP-movement in unaccusative structures as requiring passive morphosyntax (be + en). While this analysis accounts for a range of learner behaviors, it fails to capture two crucial factors: discourse-pragmatic influences and the role of subject animacy (agentivity). To address these limitations, this study proposes the Theta Misanalysis Hypothesis—the classification of the sole argument in intransitive constructions (as either an internal or an external argument) is determined by the distribution of Proto-Role properties. In L2 grammar, discourse pragmatics and subject animacy contribute to Proto-Role assignments, influencing argument interpretation. To test this hypothesis empirically, an acceptability judgment task was conducted. The experimental results revealed no significant effect of context but showed robust effects of lexical category. The findings are consistent with the Theta Misanalysis Hypothesis and offer new insights into the interaction between lexical semantics and syntax during L2 acquisition.