Humans are remarkably efficient at parsing basic linguistic cues and show an equally impressive ability to produce and parse socially indexed cues from the language(s) they encounter. In this review, we focus on the ways in which questions of justice and equality are linked to these two abilities. We discuss how social and linguistic cues are theorized to become correlated with each other, describe listeners' perceptual abilities regarding linguistic and social cognition, and address how, in the context of these abilities, language mediates individuals' negotiations with institutions and their agents-negotiations that often lead to discrimination or linguistic injustice. We review research that reports inequitable outcomes as a function of language use across education, employment, media, justice systems, housing markets, and health care institutions. Finally, we present paths forward for linguists to help fight against these discriminatory realities.