About the generation of similar words

[Rafal]

This has made me think that perhaps we are facing a type of cipher that Rafal proposed to me with the Roman numerals. A codebook cipher.

Thanks for looking at the codebook cipher option!

Let me share my position on it.
Actually I don't believe that Voynich is codebook cipher but don't exclude it. I would give about 10% of chance for that or so.

Codebook cipher is somehow strong candidate, better than a lot of things like simple substitution of European language (doesn't work), homophonic cipher (not enough symbols), syllabary, abugida, more advanced ciphers like Vignere and so on.

It is also not anachronistic, we don't have examples but it seems easy enough to be used in the 1400s.

It would be very laborious both at encoding and decoding, but I could even imagine some slightly autistic man working 5 years on Voynich Manuscript in his cell not for any practical reason but just out of passion.

The main problem I can see is that the text encoded with codebook cipher should have exactly the same structure as plain natural language. There should be nouns, verbs, conjunctions and a lot of cribs. But we don't have these.

Unless it is more advanced and words may mean full words, syllables or letters like in Great Cipher ( You are not allowed to view links. Register or Login to view. ).
But that becomes anachronistic.

So I would check first the simplest option:  one code=one word.

If we want some confirmation for "autocitation model", we should check if we cannot get the same results with codebook cipher.

My intuition is that codebook cipher may generate a lot of similar words clustered together.
Imagine some new story begins in the Bible, let's say about Noah. Several new words are introduced - Noah, Ark, flood... 
These words could get close numbers - 1221, 1222, 1223...
It will be very similar looking Latin numbers - MCCXXI, MCCXXII, MCCXXIII

I wonder how it would behave.