Misunderstandings between economic approaches to language and the field of language policy/language planning arise from deficiencies in the literature of both camps. This paper examines four examples: (1) liaison interpreting, where traditional economic analysis points to surprising benefits of engaging interpreters, often not recognised by practitioners themselves; (2) sometimes exaggerated claims by language professionals for the economic benefits of studying languages; (3) unresolved issues in language use in international organisations and trade; and (4) misinterpretations of links between multilingualism and disadvantage. Lack of understanding by economists of language issues is often matched by illiteracy in economics on the part of language professionals. (Contains 2 notes.)