Swazi is part of the Nguni group of Bantu languages and is spoken by about 1.5 million people in Swaziland and South Africa. It is one of the eleven official languages in South Africa and is taught in the schools of Swaziland, and in some South African schools. Swati, which is also known as Swazi, is closely related to Phuthi, a language spoken in Lesotho, and to Zulu, Ndebele and Xhosa.
Swati has four main dialects: Shiselweni, Hhoho, Nandzini and Shiselweni, which correspond with the four administrative regions of Swaziland.
source
wikipedia.org,
omniglot.com &
ethnologue.com