Evilspeak

Evilspeak also known as Evilspeaks is a 1981 American horror film written by Eric Weston and Joseph Garofalo and directed by Weston. It stars Clint Howard in the lead role.

In the films opening scenes, we see Satanic leader Father Estaban Richard Moll and his followers on the shore of Spain during the Dark Ages. They are approached by a church official who tells them they are banished from Spain and denied Gods grace unless they renounce Satan and their evil ways.In the present, Stanley Coopersmith Clint Howard is young cadet at an American military academy. He is also a social outcast bullied by his classmates because he is an orphan, and treated unfairly by his instructors who believe him to be inept at everything. One day, Coopersmith is being punished for no clear reason by being forced to clean the church cellar. While cleaning the darkened cellar, he finds a room belonging to Father Estaban which contains books of black magic along with Father Estabans diary. Coopersmith becomes fascinated with the book and uses his computer skills to translate it from Latin into English. In the translation he discovers that Estaban was a Satanist and the book contains rituals for performing the Black Mass along with a promise by Estaban I Will Return. Coopersmith plots his revenge on his classmates using black magic. ........

Source: Wikipedia