This article considers a fundamental issue in language planning, namely, whether or not to introduce a curriculum for the mother tongue (MT), in the wider context of a complex language planning situation in Thailand. It details recent moves in the consideration of this issue for the Thai Lao (Isan) of Northeast Thailand, Thailand's largest ethnolinguistic minority. The curriculum is being spearheaded by the Isan Culture Maintenance and Revitalization Programme (ICMRP), a four-year programme 90% funded by the European Union. The article reports on a 2012 attitude survey of 1500 purposively sampled citizens of Khon Kaen Municipality, a decentralized Thai municipality, in a comprehensive community-based mixed-method research study designed to determine whether or not to introduce the MT as a subject in the formal curriculum as part of a multilingual education. This article reports on the results of this survey, which were seen as positive, especially for the revitalization of a community script, "Tai Noi". The article concludes with a discussion, referring to Hornberger's 1994 language planning matrix, of the implications for language planning, including limitations in a sensitive area of ethnic relations and national identity.