TITLE: Predicting if something is a code
QUESTION [8 upvotes]: I'm trying to help a non-mathematical friend by posting a question of his here.  He studies literature and has come across a book which is written in a made-up language.  The book is hundreds of pages, but apparently it is unknown if there is meaning behind what's written.  Is there a standard way of predicting whether something like this is written in a code?  Obviously we can't know for sure without actually decoding it, but are there some traits to look for?  I have no idea, so I thought I would ask here.  Thanks!
Here's the book in question:
http://en.wikipedia.org/wiki/Codex_Seraphinianus

REPLY [4 votes]: The technique to investigate whether documents contain coded information is called Steganalysis. It is the counterpart of Steganography, namely hiding messages such that no one except the recipient suspects a message. The problem is generally handled with statistical analysis includig Zipf's law mentioned in the answer of Dan Piponi. For an overview see http://en.wikipedia.org/wiki/Steganalysis. And here are some valuable tools in case your problem has not yet been solved http://stegsecret.sourceforge.net/.