What does it mean to reason in economic terms, and to apply economics to an issue such as language contact? This chapter reviews basic principles (value, market, costs, benefits) and their interprets them with respect to the contrast between absolute and contingent multilingualism. It then examines a set of standard language economics issues, namely: language alongside production factors; language skills and the value creation process; net value from the standpoint of the private agent; the result: rates of return to language (and their estimation); macro-level extensions in development economics. We then turn to non-market value and to the symbolic benefits and costs of dealing with linguistic “otherness”, where we examine questions such as symbolic value at the individual level and collective level, asking ourselves whether multiple societies fare better.