Many important hominid fossils have been found in Tanzania, such as 6-million-year-old Pliocene hominid fossils. The genus Australopithecus ranged all over Africa 4 to 2 million years ago; and the oldest remains of the genus Homo are found near Lake Olduvai. Following the rise of Homo erectus 1.8 million years ago, mankind spread all over the Old World, and later in the New World and Australia under the species Homo sapiens. Homo sapiens also overtook Africa and absorbed the older archaic species and subspecies of humanity. One of the oldest known ethnic groups still existing, the Hadzabe, appears to have originated in Tanzania, and their oral history recalls ancestors who were tall and were the first to use fire, medicine, and lived in caves, much like Homo erectus or Homo heidelbergensis who lived in the same region before them.
German rule began in mainland Tanzania during the late 19th century when Germany formed German East Africa. This was followed by British rule after World War I. The mainland was governed as Tanganyika, with the Zanzibar Archipelago remaining a separate colonial jurisdiction. Following their respective independence in 1961 and 1963, the two entities merged in April 1964 to form the United Republic of Tanzania.
Over 100 different languages are spoken in Tanzania, making it the most linguistically diverse country in East Africa. The country does not have a de jure official language, although the national language is Swahili. Swahili is used in parliamentary debate, in the lower courts, and as a medium of instruction in primary school. English is used in foreign trade, in diplomacy, in higher courts, and as a medium of instruction in secondary and higher education, although the Tanzanian government is planning to discontinue English as a language of instruction altogether. Approximately 10 percent of Tanzanians speak Swahili as a first language, and up to 90 percent speak it as a second language.
The name "Tanzania" was created as a clipped compound of the names of the two states that unified to create the country: Tanganyika and Zanzibar. It consists of the first three letters of the names of the two states ("Tan" and "Zan") and the suffix, "ia" to form Tanzania.
The name "Tanganyika" is derived from the Swahili words tanga ("sail") and nyika ("uninhabited plain", "wilderness"), creating the phrase "sail in the wilderness". It is sometimes understood as a reference to Lake Tanganyika.
The name of Zanzibar comes from "zenji", the name for a local people (said to mean "black"), and the Arabic word "barr", which means coast or shore.