A strong late entry in the “significant word of 2009” sweepstakes would be the noun and verb “conlang”. A conlang is any consciously constructed language; familiar examples include “auxlangs” developed in earnest for international use, like Esperanto, but the hot new conlang is the tongue developed for the giant soft-porn Smurfs in James Cameron’s Avatar by business professor and linguist Paul Frommer.
The best-known precursors of the Na’vi language are Marc Okrand’s Klingon language for Star Trek and the various fictional-poetic tongues developed by J.R.R. Tolkien. Tolkien was a philologist whose fictive universe seems to have been a consuming spiritual vocation that accidentally generated the Lord of the Rings books as side effects. Assigning features of real human languages to the tongues of different imaginary races came naturally to him, and he probably never anticipated that these languages would become objects of passionate study and popular extension. Okrand was hired to add realism to the Trek universe, building on a small vocabulary base devised for thespian purposes by James Doohan, but he probably knew from a start that there might be a nice little sideline in it.
What’s different now is that a conlang like Na’vi is an anticipated feature of big science-fiction projects. People would have been discouraged and hostile if James Cameron hadn’t hired a linguist. Avatar was released three days ago and fans are already pleading with Frommer for the information that will let them learn Na’vi and speak it with fellow fans. For nerds, the complexity built into Na’vi is a feature, not a bug. Like Elvish and Klingon, Frommer’s language has some un-English features, like grammatical infixes, that make it particularly “alien” to English-speaking viewers but that are found often enough in the “wild”, the world of non-constructed human languages, to be convincing.
Indeed, if there is a problem with Na’vi as an pure exercise in exobiology, it is probably the inherent human-ness necessitated by the use of human actors. If we ever do run across sentient creatures ten feet tall, their design is likely to be unrecognizable and surprising. Just for starters—well, there’s an old engineering joke about God’s curious choice to put a sewage system in a recreational area, but surely having our talk-hole be our eat-hole is an even clumsier kludge?