Using the lenses of bilingualism and social justice, I reflect on relevant conceptual and methodological issues encountered in the study of the linguistic development of heritage language speakers. Themes examined include the early but varying timing of heritage language learning; the surrounding linguistic environment, including the link between parental input and linguistic outcomes and heritage language speakers' bilingualism, multilingualism, and multilectalism; the framing of literacy in the minority language; and the unique and language-shaping experience of minoritization, often an outcome of immigration. I argue that bilingualism is gradient and that better measurement of relevant variables--particularly those related to timing, input/exposure, and literacy--can invigorate the study of heritage language development and make new and more robust insights possible. I propose that heritage speakers and their languages must be understood as connected to minoritized communities and to the experience of inequitable multilingualism.