I think it's arabic text.
That's why we can't read it. With English, our brains would fill in the missing areas and we could decipher the hidden letters. With Arabic, they keep trying to decipher but can't.
Do we have a FReeper who reads Arabic?
It looks kind of like Russian text to me.
StillProud, pinging you to this thread and Judith Anne's comment about Arabic "ghost" script. Possible.