How usage-based approaches to language can contribute to a unified theory of heritage grammars

In this paper, we argue that usage-based approaches to grammar, which specify how linguistic experience leads to grammatical knowledge through the interplay of cognitive, linguistic and social factors, have a central role to play in contributing to a unified theory of heritage language acquisition and processing with much greater explanatory adequacy. We discuss how this approach (1) offers solutions to long- standing problems in the field of heritage language research, (2) links phenomena that have been explained under diverging theoretical perspectives and (3) leads to new hypotheses and testable predictions about what we can expect heritage speakers acquire from their input. We conclude that usage-based approaches are crucial to move away from deficit-oriented perspectives on heritage grammars by taking into consideration how variation in sociolinguistic experience gives rise to differences in how heritage speakers acquire and use their language.