How could you prove that VM is gibberish?

[Mark Knowles]

I also think what Mark proposes is attractive in some way: even if the MS is meaningless, there may still be actual words or sentences hidden in there. But this would only complicate matters, because it would mean that the creators of this system not only came up with a completely unique way of generating large amounts of cohesive gibberish governed by all kinds of rules, but they also snuck in a way to use the same system for enciphering actual text. So even though I like this solution on an intuitive level, I think it is not the most likely in practice.

It seems to me that the most likely scenario is that the author generated the real text for a page using an advanced substitution cipher key of the time, such as the 1424 Milanese cipher key that I have discussed elsewhere. I suspect that the author placed the words on the page with big gaps for later filler text to be added. I think the filler text words were generated partly by copying and modifying real words from that page to make new fake words, although I suppose they could also be copied from text from other pages, and also by using a stock of variants of standard Voynichese filler words the likes of which we are all familiar.

A reader with a copy of the cipher key could generate the underlying text and could easily spot the filler words by virtue of the fact that they don't spell geninue words in the language of the text whilst the "real" words do. So it should not present much problem for the reader or the writer of the text who possesses the cipher key, but considerable problem for someone without the cipher key.