About 70 % of the people of Sudan are Muslims, some 25 % follow orthodox religions, and most of the remainder are Christians. The people of northern Sudan are predominantly Sunni Muslims (see Sunnites). Most of the people in the south either practice orthodox 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 promote greater use of Arabic in the south.