Little is known about the prehistoric domestication and cultivation of crops in the Eastern Himalayas (eastern Nepal, Bhutan, Sikkim, Arunachal Pradesh), due to a lack of archaeological and archaeobotanical research in the area. This paper reconstructs the lexical terminology for grains in the East Bodish language sub-family in Eastern Bhutan. Historical linguistic methods suggest that the immediate ancestors of the modern East Bodish speakers cultivated buckwheat (Fagopyrum) and barley (Hordeum) but not millets or rice. Buckwheat was traditionally thought to have been domesticated in Southwest China; however, this research reveals that cultivation (and potentially subsequent domestication) may have taken place among East Bodish language speakers or their ancestors. These findings also pose a challenge for studies which seek to reconstruct millets to ancestral Tibeto-Burman speaking populations.