These movies either featured conlangs or took seriously the problem of communicating with aliens (or other non-English speaking prehistoric humans).
Atlantis: The Lost Empire (2001)
featuring the voices of Michael J. Fox, James Garner, and Leonard Nimoy
[Atlantean language designed by Marc Okrand]
Fox"s character, Milo Thatch, was based on Marc Okrand.
starring Sam Worthington, Sigourney Weaver, Zoe Saldana
The movie of late 2009! The buzz around the conlang featured in Avatar has been featured in numerous articles and interviews. Click here for a compiled list of press coverage links.
The Dark Crystal (1982)
directed by Jim Henson and Frank Oz
Only snippets and words of the languages are given, but the companion book, The World of the Dark Crystal by Brian Froud, gives more details on the native language of the world Thra.
starring Timothy Hutton and John Lone
The Last Starfighter (1984)
starring Lance Guest, Dan O'Herlihy, and Robert Preston
[various alien languages]
Alex, the Earthling, requires a device attached to his clothing to understand the various aliens. It has been noted that the aliens mouths move as if they were speaking English, but the problem of understanding extraterrestrial speech is at least addressed.
The Lord of the Rings movie trilogy: The Fellowship of the Ring (2001), The Two Towers (2002), The Return of the King (2003)
starring Elijah Wood, Ian McKellen, Orlando Bloom, Viggo Mortensen, etc.
[Sindarin, Neo-Khuzdul, Black Speech, etc.]
David Salo wrote dialogue in both Tolkien's languages as well as "expanded" versions of languages like Khuzdul and the Black Speech.
The Mummy (1999) and The Mummy Returns (2001)
starring Brendan Fraser, Arnold Vosloo, Rachel Weisz, and Oded Fehr
Dr. Stuart Tyson Smith, an expert in the pronunciation of Ancient Egyptian, worked on these movies as well as Stargate (see below). He was personally happier with the dialogue in Stargate, having been on set during most of the shooting. For The Mummy movies, his work consisted mostly of translating dialogue and making suggestions.) Ancient Egyptian is included in the list of movies with conlangs since spoken Ancience Egyptian is (at the very least) a reconstructed language. Click here to see an article about Dr. Smith (at the bottom of the linked page).
Star Trek: The Motion Picture (1979); Star Trek II: The Wrath of Khan (1982); Star Trek III: The Search for Spock (1984); Star Trek V: The Final Frontier (1989); Star Trek VI: The Undiscovered Country (1991); Star Trek: Generations (1994)
starring William Shatner, Leonard Nimoy, Patrick Stewart, et al.
The original Vulcan and Klingon language phonemes were devised by James Doohan; however, it is Marc Okrand who deserves credit for bringing these languages to life. Okrandian Vulcan came first in Star Trek II, while Okrandian Klingon made its debut in Star Trek III.
Star Wars Saga, Episodes I through VI (1977-2005)
The track record for the use of alien languages in the Star Wars saga is spotty; however, there are some noteworthy examples. Greedo (the assassin in Episode IV), Jabba the Hutt, the Wookies, the Ewoks, Yoda (his odd OSV sentence structure) and others were given authentic sounding dialogue in ?heir own languages. Ben Burtt, sound engineer for the productions, often used interesting combinations of sounds, not actual conlangs, for the characters. An interesting essay on this topic is published as an appendix to Star Wars: Galactic Phrase Book & Travel Guide: A Language Guide to the Galaxy.
The Time Machine (2002)
starring Guy Pearce, Samantha Mumba, and Jeremy Irons
Loosely based on H.G. Wells book. A nice exposition of the Eloi language is available at www.langmaker.com/eloi.htm.
Youth Without Youth (2007)
starring Tim Roth, directed by Francis Ford Coppola
[unnamed artificial language]
This film was based on the book by Mircea Eliade. To get more information about the artificial language (created by Dr. David Shulman) check out the official site under the "Languages" section of The Production.