"Tay" (Tày, Tho, Thu) is a general term used in reference to the large, rural, Thai-speaking population in Vietnam, primarily in northern Vietnam. In 1985, the total number of people classified as "Tay" was 1,190,342, making them the largest ethnic population in Vietnam other than the Vietnamese themselves. Tay are an official national minority in Vietnam. It is not clear, however, what specific groups fall within the official definition of "Tay." The Tay were previously often referred to as "Tho," meaning "soil," but the term is now considered derogatory and "Tay" is preferred. The Tay have traditionally been agriculturalists, growing rice in pad-Dies and by swiddening and also raising maize, buckwheat, watercress, sugar cane, manioc, and various other vegetables for home use. Tay villages were centers of regional economic activities, with local markets rotating among a series of villages. Markets often involved trade between the Tay and Vietnamese and Chinese merchants. Today, the Tay are highly assimilated into Vietnamese society.
Hickey, Gerald C. (1958). "Social Systems of Northern Viet Nam: A Study of Systems in Contact." Ph.D. Dissertation, University of Chicago.
Hickey, Gerald C. (1964). "Tho." In Ethnic Groups of Mainland Southeast Asia, edited by Frank M. LeBar, Gerald C. Hickey, and John K. Musgrave, 232-235. New Haven: HRAF Press.