This chapter briefly describes the state of the art of linguistic research on the main language families represented in Southeast Asia: Austroasiatic, Austronesian, Tai-Kadai, Hmong-Mien, and Sino-Tibetan. It reviews the vocabulary of agriculture, and more generally of subsistence, that can be reconstructed to each family’s proto-language. It attempts to clarify the dates and locations of the respective proto-languages and to throw light on the circumstances surrounding the population expansions that gave rise to them. The deepest linguistic divide in the region is thought to be between Austroasiatic and the rest. Kra-Dai is regarded as a subgroup of Austronesian. Based on original observations by M. Ratliff, the author suggests that Hmong-Mien and Austronesian (including Kra-Dai) are sister families. It is further argued that this large south-eastern group is related to Sino-Tibetan, with an origin in the language of the Císhān-Péilǐgāng culture of northern Chinese neolithic millet farmers.