If you haven't read Clackson and Horrocks' The Blackwell History of the Latin Language, I strongly recommend picking it up - if you're interested in Latin, it is one of the most technical studies of the language available in (popular) print.
The authors address the issue of "Christian Latin", a topic I've previously written about on these pages. What follows is a reflection upon Clackson and Horrocks' treatment of the topic . As I write this, I am including data that was not included in the book though is common place in Latin scholarship - in other words, this reflection is not solely based on Clackson and Horrocks.
The idea of a distinctive Christian liturgical Latin is popular among new liturgical movement types and at least one major figure (Lang) has argued in defense of the notion. The search for a Christian (liturgical) Latin has been conducted largely in relative isolation from the scholarly investigation into the origins and development of the Latin language. Largely because it has to be; "Christian Latin" cannot be substantiated by sound linguistic scholarship. In its contemporary conception, "Christian Latin" is not only subject to a serious deficiency of historical linguistic evidence, it is also a confusion of ideas as to what "Christian Latin" actually means.
Schrijen made the first attempt to present a registrar of "Christian Latin" to the scholarly community. His work rested upon rhetorical devices utilized by Christian authors in Late Antiquity to present themselves as addressing the poor and humble as opposed to the elite audience of Classical Latin authors. Schrijen justified his case for what Clackson and Horrocks refer to as a social dialect covering the expanse of the Latin portion of the Empire by appealing to "peculiarities" (a generous description, to be sure - "corruptions" might also suffice) among a handful of Christian authors. Schrijen's thesis was rejected by linguists. Schrijen's thesis, though certainly pious, ignored the technical Latin of Tertullian and the blatant attempts by such authors as Augustine to present Christian literature in a style of Latin that was comparable to the pillars of Classical Latin literature. Instances where the Latin of Christian authors can be said to be of a more simple construction than that of pagan authors were the result of the diversity of socio-economic circumstance among authors and the influence of Vetus Latina and Vulgate text. Both the Vetus Latina and the Vulgate have degrees of simplification from Classical Latin and, one can argue, are more accessible than the writings of, say, Augustine. One could describe both textual bases as Late Latin, which itself was a decline from the classical standard. I vigorously disagree with those who would try to classify the Vulgate as Classical Latin - there are too many instances of grammar and syntax that would not be found in Classical texts. There are points at which one can argue Vulgate reflects spoken use of the language; any Late Latin text that makes no attempt to mimic the Classical standard does, to one degree or another, utilize varying amounts of vocabulary and grammar reflective of spoken Latin. Both the Vetus Latina and Vulgate were, it seems, Latin text that would have been readily comprehended by the vulgus, though they could hardly be defined as written presentations of vulgar Latin.
The often cited Christine Morhmann continued the cause of "Christian liturgical Latin," making many of the same mistakes as her predecessor. Like Schrijen, Morhmann failed to account for the wide variance of "quality" among Latin Christian authors. Morhmann focused largely upon liturgical texts. With no accounting of patristic texts that were written in emulation of the classical standard, Morhmann analyzed the texts from the Roman liturgy in nearly total isolation. Pieces that were more technical (though still not meeting the Classical standard) were obvious candidates to support a thesis that liturgical Latin was not reflective of every day speech and not reflective of the language of the people. This led Morhmann to characterize (and I'm being a little flippant with my description here) other pieces of the Roman liturgy that were ridden with grammatical peculiarities/corruptions from Classical and even Late Latin as being actually technical and somewhat arcane form of Latin reserved only for liturgical use. Like her predecessor, Morhmann made no account of the influence the Vetus Latina and the Vulgate had upon those Latin Christian authors who had little if any command of the Classical standard. The Latin of the Roman liturgy, whether the pre-conciliar Missale Romanum of the Gregorian of Old Gelesian Scaramentaries, is not of the technical mastery of Cicero nor the valiant attempt to duplicate such mastery as is found in Augustine. It is right in line with the Latin of the Vulgate and, at times, serves up a number of neologisms (particularly in the Missale Romanum) indicating the influence of the Romance languages. At many points, the Latin of the Roman liturgy reflects a greater degree of simplification than the Vulgate, indicating, in my estimation, a closer proximity to the spoken language.
One can see how the argument for a type of "Christian Latin" had become confused. What Schrijen identified as evidence of a language that reflected the speech of the people as opposed to the elite audience of Classical authors, Morhmann interpreted as indicating a manner of using the language that was alien to immediate comprehension. A thorough survey of the evidence refutes the claims of both authors, so much so that Latin scholarship only writes about the topic of "Christian Latin" to demonstrate how inadequate the research of Schrijen and Mohrmann was.
Which brings us to Uwe Michael Lang and those persons who style themselves as comprising a new liturgical movement. Lang, in my estimation, has done little more than resurrect Morhmann's thesis to an audience ready and willing to believe and more than willing to ignore the larger body of historical-linguistic data that soundly refutes such an argument. If there is one hallmark of persons who identify themselves with a new liturgical movement or a "restorationist" movement, it is the shoddy standards of scholarship, the willingness to simply ignore a substantial amount of data in favor of constructing a version of history that successfully meets ideological expectations. If there is one distinct trait of contemporary "restorationist" scholarship, it is the lack of intellectual validity.