As of 2007, there were close to 350,000 individuals who spoke Krio as a primary language. Even more individuals were using it as a main language for communication purposes in the country as a whole. Language origins One theory suggests the early roots of Krio go back to the Atlantic slave trade era in the 17th and 18th centuries when an English-based "pidgin" language (West African Pidgin English, also called Guinea Coast Creole English) arose to facilitate the coastal trade between Europeans and Africans. This early pidgin later became the lingua franca of regional trade among West Africans themselves and likely spread up the river systems to the African interior. After the founding of Freetown, this preexisting pidgin was incorporated into the speech of the various groups of freed slaves landed in Sierra Leone between 1787 and about 1855. The pidgin gradually evolved to become a stable language, the native language of descendants of the freed slaves (which are now a distinct ethnic and cultural group, the Creoles), and the lingua franca of Sierra Leone. Language usage Krio usage in Sierra Leone Most ethnic and cultural Creoles live in and around Freetown, the capital of Sierra Leone, and their community accounts for about 3% to 6% of Sierra Leone's total population (Freetown is the province where the returned slaves from London and Nova Scotia settled). However, because of their cultural influence in Sierra Leone, especially during the period of colonial rule, their language is used as the lingua franca among all the ethnic groups in Sierra Leone. Krio speakers abroad The Sierra Leone Creole people acted as traders and missionaries in other parts of West Africa during the 19th century, and as a result, there are also Krio-speaking communities in The Gambia, Nigeria, Cameroon, Equatorial Guinea, Senegal, and Guinea. As a result of Sierra Leone Creole migratory patterns, in the Gambia, the Gambian Creoles or Aku community speak Krio. The Fernando Po Creole English language of Equatorial Guinea is also largely a result of Sierra Leone Creole migrants. A small number of liberated Africans returned to the land of their origins, such as the Saros of Nigeria who not only took their Western names with them but also imported Krio words like sabi into Nigerian Pidgin English. Language revival During the period of colonial rule, Sierra Leoneans (particularly among the upper class) were discouraged from speaking Krio; but after independence