Identification. The Tonga occupy much of Southern Province in Zambia (formerly Northern Rhodesia), spilling over on the east into Zimbabwe (once Southern Rhodesia or Rhodesia). Tonga in Kalomo and Livingstone districts are known as Toka; to the north are Plateau Tonga; Gwembe Tonga live in Gwembe District and in nearby Zimbabwe. The Tonga never formed a single political unit. Today they are an ethnic group united by common language and in opposition to other Zambian ethnic groups, with whom they compete.
Location. Tonga country, Butonga, lies between 16° and 18° S and 26° and 29° E, bounded on the north by the Kafue and Sanyati rivers, in Zambia and Zimbabwe, respectively. Its southern boundary follows the Zambezi and Gwai rivers. It includes the southern Zambian plateau, which rises to more than 1,000 meters, the escarpment hills facing the Middle Zambezi Valley, the Zambezi plain lying some 600 meters below the plateau, and the escarpment hills within Zimbabwe. The Middle Zambezi Valley is knows as Gwembe Valley. Average annual rainfall varies from nearly 80 centimeters at the escarpment edges to 40 centimeters in northern Gwembe Valley. Drought years are frequent. Rains are expected by mid-November and taper off through March and April, when the cold dry season begins. June and July may bring light frost. In late August the hot dry season begins abruptly. Temperatures in northern Gwembe may reach 45° C. The Zambian Railway and a highway paralleling it cross the plateau south to north, giving access to markets for agricultural produce first created when copper mines were opened in Zaire and Zambia in the 1920s. This led to European farming settlement, the building of small townships dominated by Indian shopkeepers, and cash cropping by Plateau Tonga. Since the completion of Kriba Hydroelectric Dam in 1958, much of the Zambezi plain and the lower reaches of its tributary rivers have been flooded by Kariba Lake. Over 54,000 Gwembe Tonga were displaced from the river plain to new habitats in the hills above Kariba Lake or in more arid country below Kariba Dam. They also became more accessible.
Demography. In 1980 Southern Province had an estimated population of 791,296, at an average density of 7.9 per square kilometer, some of whom were non-Tonga immigrants. Many Tonga have emigrated to Central Province since the 1940s in search of agricultural land or urban jobs. In 1969 Tonga speakers comprised slightly over 10 percent of the Zambian population; in the 1980s they probably numbered over 800,000. There were approximately 40,000 Tonga settled in Zimbabwe in the 1950s. Birthrates are high; the rate of population increase is around 2.8 percent per annum.
Linguistic Affiliation. The Tonga speak dialects of ciTonga, a Central Bantu language, along with other languages of central and northern Zambia and adjacent regions in Zaire. It was committed to writing by missionaries in the early twentieth century and today has a minute literature, but Tonga writers prefer to write in English, the official language of Zambia. The Central Plateau dialect is becoming the standard used in schools and for broadcasting.