The propositions of a scientific theory are connected with empirical states of affairs. Determining how theoretical propositions are connected with empirical facts, what Carnap called the “empirical significance” of a theory, is a complex affair. Carnap’s account of the relationship between theoretical frameworks and methods of observation has come in for plentiful criticism, alleging that Carnap’s theory of science does not allow for a sophisticated entwinement of theory and observation, instead favoring heavy formalism and a brittle reductionism. I present evidence that Carnap’s account of the distinction between theoretical and observation languages is more flexible than it is usually depicted to be and is motivated by his philosophy of science. In particular, in his mature work Carnap argues that the "specific calculus" of a scientific theory, including mathematical structure and physical laws, are included in the axiomatic foundations and linguistic framework of that theory. Carnap’s account of language thus turns out to be deeply entangled with his philosophy of science, and one cannot be understood independently of the other.