The official language of Benin is French, with several indigenous languages such as Fon, Bariba, Yoruba and Dendi also being commonly spoken. The largest religious group in Benin is Roman Catholicism, followed closely by Islam, Vodun (commonly referred to as Voodoo outside the country) and Protestantism. Benin is a member of the United Nations, the African Union, the Economic Community of West African States, the Organisation of Islamic Cooperation, the South Atlantic Peace and Cooperation Zone, La Francophonie, the Community of Sahel–Saharan States, the African Petroleum Producers Association and the Niger Basin Authority.