A central mystery in cognitive science is the remarkable consistency of language learning, in light of the tremendous variation in language-learning environments across the world. While contextual diversity is key to solving this mystery, the vast majority of research has taken place in Western, child-centric settings, arguably resulting in models of development that are ‘overfit’ to a particular learning context. This course will discuss developing evidence from diverse environments and populations, ranging from rural indigenous to industrialized, multilingual to monolingual, and speaking to signing, and prepare students to develop their own research programs via experience with a range of empirical approaches to language and sociocognitive development, including both observational and experimental methods.