Aren't there some people who can actually speak elvish? I mean, there's a Quenya course on Ardalambion (never did it, though)...

'Is it possible to speak Quenya and Sindarin?

'No. The vocabulary, grammar, and syntax of Tolkien's invented languages, even of Quenya and Sindarin, are far too incomplete to allow its casual, conversational, or quotidian use. As Tolkien himself stated, "It should be obvious that if it is possible to compose fragments of verse in Quenya and Sindarin, those languages (and their relations one to another) must have reached a fairly high degree of organization — though of course, far from completeness, either in vocabulary, or in idiom" (Letters p. 380). (What's more, it is plain that nearly every occasion upon which Tolkien set about to compose in one of his invented languages resulted in a flurry of new invention, reconsideration, and change; so that the fact that he could compose something at one time did not mean that either the result or its bases were fixed, either at that time or at any time thereafter.) Indeed, it was never Tolkien's intent to make Quenya, Sindarin, or any of his languages into spoken, written, auxiliary, or otherwise "useful" forms; rather, they were done for purely personal enjoyment. As Tolkien wrote, "It must be emphasized that this process of invention was/is a private enterprise undertaken to give pleasure to myself by giving expression to my personal linguistic aesthetic or taste and its fluctuations" (ibid.)'

'The inescapable fact is that no one can learn to speak a language without a corrective speaker or model against which to gauge grammaticality and comprehensibility (be it an already fluent speaker or speech community, or a comprehensive, fully descriptive grammar and pedagogical course). Since Tolkien never fixed his languages firmly or described them completely enough to provide any such comprehensive and corrective model (that never being his goal), and since thus even Tolkien himself was never able to speak Quenya or Sindarin fluently or casually (that too never being his goal), it is consequently a further inescapable fact that no one has or ever will be able to speak Quenya and Sindarin, any more than anyone will ever (again) be able to speak, say, Etruscan or any other fragmentarily-attested non-living language. This is not to say that it is impossible or meaningless to compose sentences that so far as anyone now can tell conform to the exemplars and statements that Tolkien did make to a very high degree (for example, by relying only upon attested elements and derivational mechanisms, attested grammatical devices, and attested syntactic patterns that can reasonably be thought to belong to the same conceptual phase), but that is a far cry from being able to speak these languages, and cannot even justify a claim of "authenticity", since for any but the most trivial compositions it will remain exceedingly unlikely that Tolkien himself would have produced or countenanced the result himself.'

'(...) It must be remembered that Tolkien is the sole and final authority on his languages; anything not written by Tolkien is strictly speaking not Quenya or Sindarin, but is simply more or less reasonable conjecture based on a selective set of data and supposed facts derived from them.

'This is not to say that the artificial, homogenized Quenya presented on Helge Fauskanger's Ardalambion site, or the pseudo-Sindarin inventions of David Salo for Peter Jackson's films, are without interest or merit (but neither are they without serious problems); but rather that meaningful study of Tolkien's languages cannot be achieved simply by mastering the artificial, simplified, patch-work systems of these popularizers. Instead, the study must be always and primarily based and centered on reading, pondering, and understanding the exemplars and statements that Tolkien himself made, in their context and in relation to one another, across the decades of his life and the millennia of internal development they were created by Tolkien to exhibit.'

I don't think it would matter that much if they used the movie version on facebook... just because it's not perfect doesn't mean they can't use it!