Sesotho is the Sotho language (Southern Sotho) of the Basotho people, an official language in Lesotho, South Africa. It is a Southern Bantu language belonging to the Niger-Congo language family and part of the Sotho-Tswana group. It is one of the eleven official languages of South Africa. Most Sotho (both northern and southern) are spoken most heavily in and around Lesotho in South Africa. The Ethnologue website will give you more specific information about its distribution and statistics.