There is much debate about the secret writing on the faces and backs of the Arcane deck. The speculation runs rampant in this thread from the Ellusionist forums.
As always, the truth is much more interesting. It is a language known as Arcanic. Spoken with a wheezy, wizardly accent, the language was used exclusively by Norse magicians who were sick of looking at the futhark runes and wanted to use a different font for their Macs. Thus they were able to hide the secrets of their magic tricks in plain sight.
The language was lost, until the Icelandic musical geniuses of Sigur Ros discovered it and used it exclusively for the () CD. The translation on the back of each Arcane card is this: "The Pass is like life: It will never be perfect, but you'll never stop living it."