A word can be spoken in different ways by different individuals, depending on many factors, such as the time in which they grew up, the area in which they grew up, the area in which they now live, their social class, and their education. Note that the word is spelled pronunciation, not pronounciation.
Linguistic terminology
The way in which an individual pronounces words depends firstly on the basic units of sound (phones) that they use in their language. The branch of linguistics which studies these units of sound is phonetics. Phones which play the same role are grouped together into classes called phonemes; the study of these is phonemics.
According to correspondants who have seen previews of The Passion, in the film Latin is spoken in the Italianate pronounciation, that is, in the pronounciation generally used in the Roman Catholic Church in Italy and the United States.
The most obvious difference between the Italianate pronounciation and the classical pronounciation is the use before [e] and [i] of the palatal affricates [tɕ] (as in cheese) and [ʤ] (as in judge) in place of the velar stops [k] (usually written ) and [g] respectively.
According to Allen, that pronounciation didn't arise until at least the fifth century C.E. By the way, although it has pride of place due to the role of the Italian clergy in the church, the Italianate pronounciation is not the only one used in the Catholic church.
The union of pronounciation of Coptic and Greek was one of the demanded requests as was witnessed.
Rehellinizaton of vocubulary in the context of re-Hellenization (Greekanization) of pronounciation:
The fundamental feature of Greco-Bohairic pronounciation is that its basic character which shifted Coptic from natural language to a semi-artificial one, by imposing an atrificial pronounciation, this lead to tensions rising due to the difference of the nature between natural languages and artificial ones.