More than half of Guatemalans are descendants of indigenous Mayan peoples. Westernized Mayans and mestizos (mixed European and indigenous ancestry) are known as Ladinos. Most of Guatemala's population is rural, though urbanization is accelerating. The predominant religion is Roman Catholicism, into which many indigenous Guatemalans have incorporated traditional forms of worship. Protestantism and traditional Mayan religions are practiced by an estimated 40% and 1% of the population, respectively. Though the official language is Spanish, it is not universally understood among the indigenous population. However, the peace accords signed in December 1996 provide for the translation of some official documents and voting materials into several indigenous languages (see summary of main substantive accords).