SiSwati, sometimes called Swati or Swazi, is the national language of Eswatini (formerly known as Swaziland), and it is also one of the eleven official languages of South Africa. The change of name from Swaziland to Eswatini was made official through a gazette signed by King Mswati III on April 19, 2018. Both siSwati and English (the language of the former colonial power) are two official languages, and both languages are the languages of proceedings in the Parliament of Eswatini. English is the medium of instruction in schools and is the prerequisite for admission into most post-secondary institutions.

About 1.27 million people in Eswatini speak siSwati, along with an equal number in the Mpumalanga Province of the Republic of South Africa (the Eastern Transvaal) for an approximate total 2.5 million speakers. Contemporary classification systems place siSwati as one of the Nguni languages of the south-eastern branch of the Bantu languages, isiZulu and isiXhosa being the other two major languages of the Nguni group.