This review summarizes a range of theoretical approaches to language acquisition. It argues that language representations emerge from interactions at all levels from brain to society. Simple learning mechanisms, operating in and across the human systems for perception, motor-action and cognition as they are exposed to language data as part of a social environment, suffice to drive the emergence of complex language representations. Connectionism provides a set of computational tools for exploring the conditions under which emergent properties arise. I present various simulations of emergence of linguistic regularity for illustration.