Mutual engagement between psycholinguistic and variationist sociolinguistic research is important: work to date shows quite different outcomes from these approaches. This chapter illustrates that, in general, heritage speakers maintain the grammatical structures and vocabulary of homeland varieties, in contradiction to widely held beliefs that language quickly “degrades” or is “bastardized” in immigrant communities, and in contradiction to many published studies about heritage languages. However, both approaches converge on finding change in one phonetic pattern in some of the languages analyzed. In this chapter, the potential sources of this apparent contradiction are explored, considering differences related to population, sample, methods of data collection, analysis, and predictors. This allows us to better understand whether, for example, reported “deficits” among heritage language speakers might be partly due to a deficit in test-taking and experience with formal contexts in the heritage language. It closes with a proposal for more coordinated work across methods.