Interlac
In the DC Comics fictional universe, Interlac is the designated communication language of the 30th century United Planets.
In its basic form it corresponds perfectly to the twenty-six letters of the Latin alphabet and the numbering system corresponds to Earth Base-Ten form.
- "As the official U.P. language, Interlac is taught in schools throughout the system and is the common form of communication between most sentient United Planet races." (After "Who's Who in the Legion of Super-Heroes #1" - DC Comics 1988)
The first reference to Interlac as the "intergalactic universal language of the 30th century" was in Adventure Comics #379 published March, 1969. It was also frequently referred to in the Super Friends comic book series (in which all of the Super Friends, including Wendy and Marvin, speak it) as a token explanation of how the Super Friends could understand the language of visiting and/or invading extraterrestrials.
Although completely unrelated to DC Comics, Babylon 5 occasionally made reference to an interstellar language used as an auxiliary form of communication and for trade purposes called "Interlac." As Joe Straczynski is an avid fan of the Legion of Superheroes, the similarity is likely not a coincidence. [1]
In the Babylon 5 universe, Interlac is also referred to as a universal language most often used in first contact situations because it is easily translated. It is easily translated due to the fact that it is a language based on pure mathematics. Note that in this context, it is normally used only in first contact situations until such a time as a more common understanding between two new species becomes available. Unlike the DC Comics version of the language, the common trade language in the Babylon 5 universe is English.
Recent Usage
In the Justice League of America / Justice Society of America crossover, Interlac is spoken by the character Starman as a trigger. He says "lightning" in Interlac, freeing his fellow Legion members from whatever pyschological blocks that have been put in place.