Verbal morphology has been identified as a particularly vulnerable domain for adult heritage speakers (HSs) of Spanish, especially when it involves the selection of subjunctive mood. A minimal amount is known, however, about the potential effects of the variability associated with these forms on the acquisition of related epiphenomena, such as the…

I review the classic literature in generative grammar and Marr's three-level program for cognitive science to defend the Evaluation Metric as a psychological theory of language learning. Focusing on well-established facts of language variation, change, and use, I argue that optimal statistical principles embodied in Bayesian inference models are…