It is widely recognized that the processor has a key role to play in creating and strengthening the mapping between form and meaning that is integral to language use. Adopting an emergentist approach to heritage language acquisition, the current study considers the extent to which the operation of the processor can contribute to an account of what is acquired, what is subsequently retained or lost, and what is never acquired in the first place. These questions are explored from two perspectives. First, morphosyntactic phenomena for which there is apparently substantial input are considered, with a focus on the relevance of salience, frequency, and transparency to the establishment of form-meaning mappings. Second, a phenomenon for which there appears to be relatively little input (i.e., scope) is examined with a view to understanding its fate in heritage language acquisition. In both cases, the emergentist perspective appears to offer promising insights into why heritage language learners succeed—and fail—in the way that they do.