After that the Thessalonians had been well instructed in the faith, persecution, which perpetually followeth the preaching of the Gospel, arose, against the which although they did constantly stand, yet Paul (as most careful for them) sent Timothy to strengthen them, who sown after admonishing him of their estate, gave occasion to the Apostle to confirm them by divers arguments to be constant in faith, and to suffer whatsoever God calleth them unto for the testimony of the Gospel, exhorting them to declare by their godly living the purity of their religion. And as the Church can never be so purged, that some cockle remain not among the wheat, so there were among them wicked men, which by moving vain and curious questions to overthrow their faith, taught falsely, as touching the point of the resurrection from the dead; whereof he briefly instructeth them what to think, earnestly forbidding them to seek curiously to know the times, willing them rather to watch lest the sudden coming of Christ come upon them at unawares; and so after certain exhortations, and his commendations to the brethren, he endeth.
This is the introduction to Paul's First Letter to the Thessalonians in the Geneva Bible. It came up as I was commenting about changes in language. I noted that Shakespeare and the King James Bible remained somewhat understandable mostly because the phrases in them had dominated English afterward. Contemporary writing which did not bequeath so many phrases to us is less understandable. The Geneva Bible is a good example. Though it came into being fifty years earlier, it used more modern phrasing of the time - even then, the KJV gravitated toward the slightly archaic in order to be poetic.
Nonetheless, even with more modern language, the unfamiliar passage from the Geneva is harder to understand, and we see why it begins to creep beyond being merely a different dialect of English, on into being considered a separate language. We know most of the words, but some are unfamiliar or seem to have different meanings or frequency than we are used to. The word-order is significantly different, as is the phrasing.
We get the sense of it, especially if we are familiar with the New Testament in any translation, so that the concepts are more easily grasped. But stand in the shoes of a highschooler with no Christian training - this is nearly a foreign language.