In the first episode of Hataraku Maou-sama, what is the "Underworld" language based on? In the first half of the first episode of Hataraku Maou-sama, we can hear conversation between Satan and Alsiel in "Underworld" language. Is the "Underworld" language based on a real language, or is it just plain gibberish?
According to this article (which cites from a 2ch thread), the language is is pretty simple:

The Entean language is basically letter substituted English, with vowel keeping their original position, while the consonants are reversed, so B=Z, C=Y, D=X, ... and vice versa.
   ABCDEFGHIJKLMNOPQRSTUVWXYZ
-&gt; AZYXEWVTISRLPNOMQKJHUGFDCB

For example:

人間 human → tupan
世界 world → foklx
魔王（芦屋による呼称） majesty → pasejhc


They say it with such enthusiasm, too:
http://www.youtube.com/watch?v=lSwnNy6MRa8