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…

The Bottleneck Hypothesis argues that properties of inflectional morphology explain why second-language learners may face persistent difficulties in articulating meaning in target-language forms. In particular, the acquisition task proves even harder when first and second languages differ in the way they organize the mapping of functional features…