The Ambundu or Mbundu (Mbundu: Ambundu or Akwambundu, singular: Mumbundu (distinct from the Ovimbundu) are a Bantu people who live on a high plateau in present-day Angola just north of the Kwanza River. The Ambundu speak Kimbundu, and most also speak the official language of the country, Portuguese. They are the second biggest ethnic group in the country and make up 25% of the total population of Angola. The Ambundu nowadays live in the region stretching to the East from Angola's capital city of Luanda (see map). They are predominant in the Bengo and Malanje provinces and in neighbouring parts of the Cuanza Norte and Cuanza Sul provinces. The head of the main Ambundu kingdom was called a Ngola, which is the origin of the name of the country Angola. The Mbundu speak the Kimbundu language, which has two dialects: Akwaluanda and Ambakista. Spoken in Luanda in the west, Akwaluanda (also referred to as Ambundu) developed from interactions between Kimbundu speakers and other ethnic groups in the region. Spoken in Ambacca in the east, Ambakista developed from interactions between Kimbundu speakers and Portuguese traders. The exact origin of the Mbundu people is unknown, but there are some oral traditions that were passed down through the generations. The first oral tradition says that the Mbundu came from "the great water." Many historians interpreted this as the Atlantic Ocean and cite their origin as Luanda Island. This oral tradition also speaks of five great ancestors of the Mbundu: Zundu dya Mbulu, the mother of the Ndongo people; Kajinga ka Mbulu, founder of the Mbondo Kingdom; Matamba a Mulu, mother of the Pende people; and Kongo dya Mbulu, founder of the Hungu people. The second oral tradition records that a man named Mussuri rose from ironworker to king of the Mbundu. After marrying a woman named Ngola Inene, they are said to have birthed a daughter named Samba. Samba gave birth to 8 children, who later begot the Ndongo, the Mbondo, the Pende, the Hungu, the Lenge, the Imbangala, the Songo and the Libolo people.