Draw a line on a map from Cameroon in the west to Kenya in the east. South of it, across most of the continent, people speak languages so closely related that a speaker of Swahili in Tanzania and a speaker of Zulu in South Africa will recognize many of each other's words. Today about 350 million people speak Bantu languages, of which there are several hundred, often counted at around 500. How did one family of languages come to cover so much ground? The answer was pieced together almost entirely without written sources.
A name and a family
In the nineteenth century European linguists noticed the family's resemblances. The German linguist Wilhelm Bleek built the name Bantu from a word meaning "people": in many of these languages the root -ntu means person, and ba- marks the plural. Later work by the American linguist Joseph Greenberg placed Bantu as one branch of the vast Niger-Congo family, which stretches across West Africa. Because the deepest divisions within Bantu, and its closest relatives, are found in one corner of the continent, Bantu languages most likely originated in the borderlands of eastern Nigeria and western Cameroon.
Not an invasion
Older textbooks pictured a great wave of Bantu warriors sweeping across Africa. The evidence does not support that picture. Beginning perhaps four to five thousand years ago, small farming communities moved, a few kilometers per generation, along rivers and the edges of the rainforest. One broad stream went south through the forest toward Angola; another reached the Great Lakes region of East Africa by the first millennium BC and later turned south. Historians now describe the Bantu expansion as slow movements over millennia, mixing with peoples already there, not as a single migration. Languages spread as often by people joining farming villages, marrying in and shifting tongues as by newcomers replacing anyone.
Farming, iron and new crops
The earliest Bantu speakers grew yams, used oil palms, kept goats, made pottery and fished from canoes. As they moved east they met speakers of other language families and took up grain crops such as sorghum and millet, along with cattle. A crop from far away also mattered: bananas were first domesticated in Southeast Asia and New Guinea and reached Africa, probably by sea, by the first millennium AD, later becoming a staple in the Great Lakes region.
Iron working spread through the same world. The Nok culture of central Nigeria is known for its terracotta sculptures and early iron smelting, dated to the first millennium BC. Whether Africans invented iron smelting on their own or learned it from elsewhere is still argued, but African smiths soon developed furnaces and techniques of their own, and iron tools made it easier to clear land.
Meeting the first peoples
Farmers were not entering empty land. Forest foragers, such as the ancestors of today's Batwa and other groups once lumped together under the outsider's label "Pygmies," lived in the rainforest. In the south lived Khoe and San peoples, herders and hunter-gatherers whose languages are very different from Bantu. Contact left traces in speech: the click consonants in Xhosa and Zulu were borrowed from Khoisan languages. Genetic studies show mixing too, though in many places foragers were pushed into marginal land and treated as inferiors.
History used as a weapon
The Bantu story has been misused. Under apartheid, South African textbooks taught that Bantu-speaking farmers had moved into the country at about the same time as Dutch settlers arrived at the Cape in 1652, implying that white South Africans had as strong a claim to the land as anyone. Archaeology shows that farming villages existed south of the Limpopo River more than a thousand years before 1652, by about AD 300 to 500. Apartheid also stamped the word Bantu onto laws and "homelands" for Black South Africans, which is why many South Africans dislike the term outside linguistics.
Worked example: reconstructing a word
How can anyone know about a language spoken thousands of years ago that nobody wrote down? Take the word for person. In Swahili it is mtu, plural watu. In Zulu it is umuntu, plural abantu. In Kikuyu, spoken in Kenya, it is mũndũ, plural andũ. In Lingala, along the Congo River, it is moto, plural bato. In Kikongo it is muntu, plural bantu.
These forms are not identical, but the differences follow regular patterns of sound change, the way Latin words changed into French and Spanish ones. Comparing many languages lets linguists reconstruct an ancestral form, written with an asterisk to show that it is inferred rather than recorded: *mu-ntu for person and *ba-ntu for people. Its vocabulary includes words for goats, yams, oil palms and canoes, while words for cattle and grain crops seem to appear only in later branches.
The same root carries one of the most famous ideas in modern Africa. Zulu and Xhosa speakers have long said that a person is a person through other persons, an idea known as ubuntu. Archbishop Desmond Tutu drew on it in arguing that South Africa could only heal if victims and perpetrators recognized each other's humanity. Even a reconstructed root can lead back to living ideas about human worth.