Imagine overhearing the voice of a 5-year-old, and not being able to tell whether you were listening to a little girl from Canada or an elderly man from Scotland. It seems almost unimaginable, and that’s because whenever we hear someone’s voice, we effortlessly make social inferences about their identity. How do children develop these kinds of abilities? What kinds of inferences do they make about others based on how they speak, and how do they convey social meaning in their own language use? In the current talk, I will present some of my research exploring these questions, focusing on children language biases (and where they come from), and how they influence children’s behavior in interactions with others (with experimenters and in peer settings). This work helps to understand the complex interplay between children’s developing linguistic and social knowledge.