Southern Sotho is one of the official languages of South Africa and is a member of the Bantu/Nguni family of languages. It is spoken by about 5 million people in Lesotho, Botswana, South Africa, Namibia and Zambia.
The first written form of Sesotho was devised by Thomas Arbousset, Eugene Casalis and Constant Gosselin, French missionaries of the Paris Evangelical Mission who arrived in Lesotho in 1833. The first grammar book, Etudes sur la Langue Sechuana by Casalis, was published in 1841.
source
wikipedia.org,
omniglot.com &
ethnologue.com