Many of the the words used by the Fremen and the people in this universe have their origins in Persian or Arabic. The name that Paul chooses for himself in Muad'Dib, which means mouse in the Fremen's language but actually comes from Arabic meaning "the teacher or maker of politeness or literature". The title of the Padishah Emperor comes from the Persian word Shah. Many Islamic terms can be found throughout the book, including jihad, Shaitan, and Mahdi. The blue eyes of the Fremen could be a reference to the distinctive blue robes of the Tuareg peoples of the Sahara Desert. The use of these words provides the reader with a sense of an oxymoronic foreign familiarity.