Language-in-education policy (decision taking) and planning (decision implementation) are complex processes requiring a number of decisions to be taken and implemented if they are to be successful. While there is research that suggests the factors that lead to successful outcomes, these are often either ignored or too difficult for polities to implement, given their resources. This insufficiency can lead to a waste of resources and a failure to meet language planning and learning objectives. A number of myths have arisen about such planning, in general, and about the role of English as a second/foreign language, in particular, relating to English being a guarantee of access to economic opportunity and about starting language study early leading to better outcomes. In this paper, we examine 12 common fallacies related to educational language planning to provide some insights into why such plans sometimes fail. This paper provides an introduction to eight polity case study papers, which follow, that highlight particular aspects of these fallacies. (Contains 3 notes.)