The Interlac alphabet is a simple one-to-one substitution cipher. The Interlac alphabet corresponds perfectly to the twenty-six letters of the Latin alphabet and the numbering system corresponds to the Earth Base-Ten form. Although nominally protected by differences in font spacing, the numbering system itself suffers from a minor stylistic flaw due to the potential for confusion of 6 with 41 and 7 with 42. Anyone writing it by hand could certainly introduce an error when read by another, and this could also create problems with handwriting recognition.

Known speakers

• Imra Ardeen
• Preya Ardeen
• Mon-El
• Winn Schott (presumed)
• Querl Dox/Brainiac 5
• Ayla's brother
• Ayla
• Other Legionnaires, Coluans, Saturnians, Winathrians, etc.
• Everyone in the United Planets (presumed)

Appearances

Supergirl

Season 2 "The Martian Chronicles" Season 3 "Girl of Steel" "The Faithful" "Wake Up" "Legion of Super-Heroes" "Fort Rozz" "Both Sides Now" "In Search of Lost Time" (mentioned) "Of Two Minds" "Trinity" "Shelter from the Storm" "Battles Lost and Won" Season 6 "Prom Night!" "Prom Again!"

Trivia

• Interlac is also shown to be the language (in the comics) of which the Guardians of the Universe (or for Earth-12 (new multiverse)) write the Book of Oa, also known as the Tome of the Guardians.
• As the official United planet's language in the Legion of Superheroes animated tv show, Interlac is taught in schools throughout the system and is the common form of communication between most sentient United Planets species. Written Interlac is present in the United Planets system, as well. From street signs to billboards to identification, Interlac is everywhere and as so generally accepted.
• It has been shown to have been used thousands of years ago in Space Sector 2, According to Blue Beetle issue 1, Of the New DC Universe.
• The origins of Interlac are purely mathematical and thus, can serve as a mode of first contact between two species until a better method of communication can be adopted.