About 70 percent of the people of Sudan are Muslims, some 15 percent are Christians, and most of the remainder follow traditional religions. The people of northern Sudan are predominantly Sunni Muslims (Sunni Islam). Most of the people in the south either practice traditional religions or are Christians. The official language of Sudan is Arabic; English is widely spoken, and African languages are used in the south. A program of Arabization is in place to encourage greater use of Arabic in the south.