Both the Amish and Mennonites are Anabaptists, Protestant groups with roots in the Radical Reformation in the 16th century. Many of them immigrated to colonial North America in the 18th century.
The Amish live by the Ordnung, a set of religious rules. The most visible outcome of the Ordnung is that some Amish to a greater or lesser degree reject modern clothing, motor vehicles and electric machinery. The Amish do not see technology in itself as evil, but they reject inventions which challenge virtues such as diligence and family ties.
While German-speaking peoples made up a large portion of European settlers in North America, the Amish are among the few who have preserved their language to present day. Their traditional language in Pennsylvania is known as Pennsylvania German, or Pennsylvania Dutch (a mispronunciation of Deutsch).