Some suggestions and theories

[SpamBot]

Voynichese itself is not a full-fledged language. The theory of an artificial language also falls away - it is too redundant. However, it can still be a modified language (German, Occitan, Bavarian, Chinese, etc.).

Any encryption (except for compression, but here it's very unlikely) is a bijective function preserving orientation (while encoded string "ABC" can be rotated in multiplies of 45deg or even reflected, the 'B' would still be between 'A' and 'C' in the output; otherwise we would have more than 1 encryption/decryption for the same piece of information) between 2 sets of (groups of) symbols, therefore any encrypted text can be cracked by a simple bruteforce. While it may look impossible with the current technology (for a set with 30 [and since the manuscipt doesn't contain punctuation and numerical symbols the actual number is going to be bigger] symbols checking all 30! bijective functions would take 100s of years on a PC capable of doing 10^9 ops/sec), we can take just 2 different words (preferably from different pages) containing the same symbols and try to crack them instead: if words are of length, for ex. 5, then we don't need more than A(50, 5) checks (50 is a random upper limit on a size of alphabet + symbols), which is very manageable. If 2 words we get this way belong to the same language (ancient Italian?) - we likely cracked the code. It's a simple trick, so I assumed that someone already tried it and it failed (none of the known languages had the resulting words). Then what other conclusion, except for existence of Voynichese, can we derive from it? Besides, the only structural difference between encrypted and unknown language is that unknown language may have unique grammar rules (like those which omit punctuation symbols). However methods of translation and decryption differ: translated are words, not symbols.

Also, how many other encrypted books (not letters, messages etc.) are there? But how many are written on a foreign language?