hamsterbait....Actually the language used in Revelation is rather dreadful, filled with solecisms and ungrammatical expressions, so most scholars tend to believe that the author learned Greek as a second language and spoke Aramaic as his native language. The problem is that the same author could not be responsible for both the Revelation and the gospel of John, as the latter definitely has a very refined and cultivated style. This was noticed in antiquity by people who spoke Greek. Dionysius of Alexandria and Eusebius denied the same author wrote both books, the former saying that the gospel and 1 John "are composed not only in faultless Greek but with great skill in their expressions, their arguments, and the arrangement or their expositions", but as for the author of Revelation, "I will not deny that he had seen revelations and received knowledge and prophecy, but I notice that his dialect and language are not correct Greek; he makes use of barbarous constructions and sometimes of actual solecisms" (apud Eusebius, Historia Ecclesiastica, 7.25). The two books also have a very different religious thought, both eschatological and theological.
Another issue is the fact that there were two different individuals named John, Apostle John and Elder John, whom Papias (who knew the latter personally) distinguished (apud Historia Ecclesiastica, 3.39). These two Johns were later confused with each other and conflated in later Christian tradition. Since 2, 3 John are attributed to the "Elder", it is probable that these were written by Elder John, not the Apostle John. But it is an incredibly thorny problem to try to sort out the relationship between 2, 3 John and 1 John, and between these epistles, the gospel, and Revelation. Some scholars attribute the gospel to Elder John and not Revelation, whereas other scholars attribute Revelation to Elder John and not the gospel. Since Elder John lived in Ephesus in Asia Minor and since the chiliasm of Revelation was popular in Phyrgia and was influential on Papias (who apparently was familiar with the book, if Andrew of Caesarea is to be believed), it is certainly more attractive to conclude that the Elder John was responsible in some way for the publication of Revelation. Since Revelation appears to incorporate an older apocalypse with parallels to the Zoroastrian/Jewish Oracles of Hystaspes (which was popular among Christians despite the fact that reading it incurred the death penalty, Justin Martyr, Apology 1.44.12), it is possible that Elder John revised a series of oracles written by someone else. As for the gospel of John, its provenance does not appear to be in Asia Minor but Syria, where we find the closest parallels in thought and content (i.e. in Ignatius of Antioch, the gospel of Thomas, and especially the Odes of Solomon). But it is also possible, on account of its inordinate focus on Jerusalem as opposed to Galilee, that its author was a Christian from Jerusalem (who published the gospel in Syria sometime subsequent to the destruction of Jerusalem in AD 70). Other problems include the oblique references to the "Beloved Disciple" (who in the context of the narrative appears to be Lazarus), the relationship of ch. 21 (with its references to the "Beloved Disciple") to the rest of the book, and the traditions in the East that the Apostle John was martyred with his brother in the early days of the Christian movement. It's a fascinating puzzle and I don't think I've seen a solution that is entirely satisfactory.
The Society however doesn't delve into any of these issues -- the striking linguistic character of Revelation, the fact that there were two Johns, the problematic relationship between the books -- it simply takes for granted the tradition that the Apostle John was responsible for authoring all the Johannine books.