American author William Peter Blatty wrote the horror novel The Exorcist, published in 1971, and he also produced and wrote the script for the classic 1973 film version—the screenplay for which he won an Academy Award. The book is an account of the demonic possession of a girl, Regan MacNeil, by a "Captain Howdy"—an alias of Pazuzu, an ancient demon—and of the desperate attempts to free her through exorcism, which is conducted by two priests.
Before we begin to translate the unforgettable scene during which coming-of-age Regan—who has already urinated on the floor at a party, performed a spider-walk, levitated a bed, and spewed pea-green vomit—profoundly speaks Latin (and French) through the Demon to Father Damien Karras, a word on exorcism. It refers to a ritual act that is addressed to evil spirits to force them to abandon an object, place, or person; in particular, an exorcism is performed in Christian religions to expel a demon or spirit from a person who has come under his or her power. The word is conjured from Anglo-French exorciscer and is ultimately, via Latin, from Greek exorkizein, from the combination of the prefix ex- ("out of," "away") and horkizein, meaning "to bind by oath" or "to adjure" (adjure also implies commanding under penalty of a curse). Greek horkos means "oath." In sum, when a priest exorcises a demon from a person, he adjures it to leave.
We will now begin our translation of the dialogue between Demon/Regan and Father Karras. Mind you, Demon/Regan just telekinetically threw open a bedside table drawer and the Father, who is trying to figure things out, asks her/it to do it again.