The place of Latin in the Roman Catholic Church has been subject to unending debate since the promulgation of Sacrosanctum Concilium at the Second Vatican Council. The arguments have been made in the form of papal pronouncements, journal or magazine articles, popular blog literature, and the occasional erudite piece of publishing. The latest entry can be found here, courtesy of the National Catholic Reporter.
Of late, I've made it policy to avoid popularly available material on the subject of Latin in the Roman Church - the quality of the research and the disposition of the writer leaving much to be desired. However, the priest interviewed for this article seems well educated and even tempered, thus making him a good, albeit mediated, dialogue partner. Fr. Gallagher makes two observations that are common place these days: the universal property of the Latin language and the cultural if nor ancestral heritage of the language.
The argument of the universal property of Latin is in some respects true. Among Romance countries or countries that eventually came under the control of the Roman Empire, Latin is a linguistic equalizer. It has been noted elsewhere, I believe by Hull in The Banished Heart, that among the Italians Latin is a neutral language. Having been the basis of the linguistic spectrum of Italy, whether Venetian, Sicilian, Calabrian, Neapolitan, or Tuscan (among others), Latin cannot be claimed by anyone one region of Italy. Where standard Italian is based off of Tuscan with some Sicilian influence (via the dominance of the Sicilian school of poetry and its influence on Dante) and, depending upon your perspective, displaced or heavily transformed many of the languages/dialects of the Italian south, Latin has no such historical baggage nor carry the cultural connotations common among the regions of Italy. Conversely, Latin IS a western European language; it has a cultural connotation all of its own and to adopt the language as one's own (liturgically speaking) makes the statement that one belongs to this linguistic culture. For persons of a cultural history outside of the influence of the Roman Empire, the adoption of Latin represents a rupture with their own cultural identity.
This leads directly into the second argument, that of cultural or even ancestral heritage. The idea that one could learn the language one's ancestors spoke has the potential to be a powerful motivator in learning a language. For my own part, that is why I learned Italian. Mr great-grandfather knew standard Italian after having been enrolled in the Italian army. The rest of my Calabrian relatives new a language that was, in my estimation, heavily influenced by the Italian koine and my Sicilian relatives knew the language that would provide the literary substrata to Standard Italian. It becomes somewhat more difficult to make the same argument for Latin. Once again, I will appeal to the Italian peninsula, but the argument applies well to most all of the Romance countries.
There are substantial debates as to when Latin was no longer understood outside of clerical or administrative circles. By about 900, a language distinct from Latin is attested to in writing in Italy. Retrospectively, we might term it an "Italian Koine", a basic model of Italo-Romance that is at that time breaking off into the many regional variants found in Italy. Some scholars have (notably, Clackson and Horrocks) have postulated the existence of a simplified Latin used in normal speech in addition to the distinctive regional vernaculars of Europe. This hypothesis is based upon hagiographical accounts which seem to imply some largely common tongue among Western European countries around the period of 900-1000, the period during which the first written evidence of Romance languages emerges in the historical narrative. This would, if true, extend into the turn of the second millennium the use of Latin as a spoken language outside of clerical or royal classes. Clackson and Horrocks are not the only scholars to have posed the existence of some form of lingua-franca around the year 1000. If you recall my review of Before the Normans, the accounts of interactions between Arabs and "Latins" in Naples and Greeks in Calabria and Sicily or the interactions between "Latins" and Greeks suggest to some historians the existence of a now lost pan-Mediterranean language. However, the existence of some simplified form of Latin used throughout Europe or a pan-Mediterranean dialect remains hypothetical. Additionally, we know from property registers of the late ninth and early tenth century that Sicily has demonstrable indications of Sicilian, Greek and Arabic all being used on the island, presumably for a substantial period of time prior to the compiling of the registry material. Latin, it seems, did not see use in Sicily from the loss of the island to Byzantium until the Norman period, although Sicilian, being derived from Latin, may have had a substantial presence on the island as a spoken language for some time, hence it's ready application in the form of glosses in the early Norman property registers.
The rise of the Italian languages/dialects in Italy is comparable to that of other Romance languages. In all cases, the historical evidence suggests that Latin had become largely unintelligible as a spoken language. Liturgically, it is unknown how much praying was done in Latin outside of the clergy, both on account of the linguistic divide and the degree to which the liturgy in the Latin west became an increasingly private affair of the priest. It is possible people memorized a Pater Noster, the content of which is easily translatable to most Romance languages. However, the majority of the liturgy, sung hymns included, remained obscured by the distinction between Latin and Romance. Although, it must be noted that Latin texts contain variable proximity to the Romance languages. The Old Latin text of the Bible, being written in Late Latin and typically reflecting patterns of Latin speech (though by no means a written record of vulgar Latin) provides a linguistic link to the Romance languages as they reflect many of the errors of proper Latin that would become standard in Romance.
It is true, however, that there is a degree of connotative content in the Latin text that is not readily translated, especially into non-Romance languages. Connotative qualities aside, there is also a matter of theological quality to much of the traditional Latin texts. At a fairly early stage, the Latin west becomes divorced from Greek and Hebrew/Aramaic. Even Jerome's work is subject to substantial debate among linguists, his knowledge of both Hebrew and Greek coming into question. It seems Jerome may not have been as able in those languages when he produced his Latin translation of the Bible as he was later in life commenting on some of the Biblical texts. The Vulgate became foundational to subsequent Latin prayer and theology. It is worth noting that said prayer, including liturgical prayer, was often based off of poor theology stemming from improper translation in both Jerome's text and/or the Old Latin recension. Quick example: it's the difference between penance in the traditional Latin translation and repentance in most modern translation. The two are very different concepts, but only one accurately translates the Greek of the New Testament.
This does not mean, however, that I would advocate a whole sale abandonment of Latin. There are reasons to retain it. As mentioned above, the Old Latin text offers us a rare window into Latin's eventual development into the Romance languages. Medieval Latin supplied much of the aesthetic foundation for Medieval European culture, reflected in both literature and art. As a language of artistic medium, Latin is more relevant today than it has been in perhaps the last two centuries, although Latin's contemporary artistic expression largely comes from some non-conventional and perhaps even non-Catholic sources. The popularity of Hildegard von Bingen's works among new agers and goths, traces of Latin chant in such groups as Dead Can Dance or indeed the full usage of the language for lyrical content by bands such as This Ascension, Medieval Babes and My Dying Bride demonstrates that the Latin language has had a renewed surge among contemporary and largely non-Catholic artists and audiences. There has been something of a resurgence among younger priests and religious, this is true. Although, the liturgy and prayer are more than the priests and religious. Indeed, it is such an emphasis on the clergy that led to the impoverishment of the Roman liturgy in the middle ages.
It is tempting to say that Latin has scarcely any practical relevance. To some degree it's true; Latin is largely relevant to specialists of language, history, theology, or (nowadays) music. I would argue, however, that Latin is relevant when freely chosen. As a person with a back ground in Biblical Studies, if I use Latin it is with full knowledge of many of the textual errors and resulting theological problems from said text. I freely choose to suspend that critical knowledge in order to enter into the world of the language itself. The challenge I would put before Latin advocates is to let Latin be similarly freely chosen in the liturgical context with full the community being fully informed and fully consenting. Of course this would require Roman Catholic parishes adopting the model of intentional religious communities. As history tends to show, the Roman Catholic church often follows the principle of conserving energy or, in more blunt terms, if the opportunity to be lazy presents itself, Roman Catholics will more often than not choose it. This is not me Catholic bashing, rather, I am making a disheartening but sobering commentary on my own religion - mediocrity is more often than not the norm.
Putting aside nostalgia, aesthetics, or papal pronouncements, Latin, I believe, does have a place. One can find no better proof than when comparing the euchological corpus of the Missale Romanum to some of the contemporary intellectually scattered and emotionally overladen drivel produced in vernacular worship today. While Latin liturgical prayer is paltry when compared to its Greek and oriental counterparts, the reserved cool and theological density of the Latin text serves to correct some of the more, if I may say, noxious trends in contemporary Christian worship.