[split] Does Voynichese evolve from A to B?

[Mauro]

Thus indeed I assume that Herbal-A and Herbal-B are about the same general topic, namely "herbal".

But even so they could have different "sub-topics".  Like, one may be concerned with tonics for long life and virility, while the other may be about women's conditions and pregnancy.  One may have astrological information, the other may have dosages and prep methods. Etc.

Yes, but again: this is not what I see in the (albeit limited) statistical comparison I have made across a few languages (and some hundreds texts, even if mostly in Italian), the results are posted in a thread somewhere. For example: the distance of bigram frequencies between Dante's Inferno and a book written in 1994 is 0.025, while for reference the distance  between Dante and Ceasar's De Bello Gallico (in the original Latin) is 0.084. The distance between VMS Herbals A and B is 0.086: same as between Italian and Latin. You can see it at glance in a plot of bigram frequencies (notice also the colour scale is about twice as wide in the Voynich case, the differences are greater than they visually look, compared to Italian):

   

   

One needs truly an extreme case to justify such a shift of statistics with a change of topics, while keeping the same 'language': possible, but very improbable.

Here is the same sentence in three dialects of Venetian (which is called a "dialect" of Italian, but is actually very distinct language).  For comparison there is also the version in standard Italian (Tuscan "dialect") and in Neapolitan, another "dialect" that is another distinct language.

• Feltre:  I fradei i è  andà  in cusina a θor le ciaf,  ma no i à  catà gnot.
  
• Venice:  I fradei i ze andai in cusina a tor  e ciavi, ma no i ga catà gnente.
  
• Verona:  I fradei i è  andà  in cosina a tòr le ciave, ma no i à  catà gnente.
  
• Italian: I fratelli sono andati in cucina a prendere le chiavi, ma non hanno trovato niente.
  
• Neapo.:  I fratielli so gghiute a cucina a piglià e chiave, ma nun hanno truvato niente.
  
• English: The brothers went to the kitchen to fetch the keys, but found nothing.
  
  

(Examples by Gemini; the Venetian and Italian seem right, not sure about the Neapolitan.)

All the best, --stolfi

In Eastern Lombard (for the sake of precision, a little north of Brescia, it can be different in other zones) I would say "I fradèy y'è nàc en küzìna a tö le càf, ma y'à mìa katàde". But this is my personal orthography, most would Italianize the orthography to an horrible "I fradei ie nacc en cusina a to le ciaf ma ia mia catade". So I rather agree with Stolfi here.