In this work, Rita Nolan criticizes ideas - among them, Fodor's "language of thought" model and Chomsky's "innateness hypothesis" - that have dominated cognitive psychology and linguistics for decades. The social practice account of language that she proposes sheds light on a host of topics (including the philosophy of the earlier and the later Wittgenstein), and leads her to a reconceptualization of the development of logical and linguistic skills in the child. How does human language contribute to the cognitive edge humans have over other species? This question eludes most current theories of language and knowledge. Incorporating research results in psychology and cutting a path through a range of philosophical debates, Nolan develops an account of language acquisition which should hold important implications for standard theories of language and the philosophical foundations of cognitive science.