The Modern Forgery Hypothesis

[eggyk]

1) Aberil was used, in print, in sufficient publications in the 18th or 19th centuries to fulfill my Theorem #1.
2) Furthermore, several references are to an "... an important Swiss epic poem written in dialect.", which reinforces #1. I mean, it was not in somebody's daily diary, it was a repeatedly published, well known and important poem
3) But as AI pointed out, above, it could also date to the era of the Voynich
4) And it may point to a Swiss/Germanic origin for these appended month names, or at least this one, whether the Voynich is old and real, or new and fake.

Rich

I will note that the AI summary snuck in an extremely important sentence, namely: "The uninflected, base root of this exact word in the 14th/15th century was Aberel or Aberil." 

This simply is not the case. Aberel is indeed correct, and so is the relatively common "in dem aberellen". Aberil is not. We have plenty of aberels and aberellen, including the Codex manesse as cited. But aberel is not the same as aberil. 

I do disagree with the phrasing of "sufficient", as it implies that the usage was widespread in print to the point that voynich was in any way likely to have seen it. It really wasn't, and the usage was still extremely niche as far as I can tell. The fact that a whole community hell-bent on finding aberil has not happened across these 'important' poems before strongly suggests that it isn't that important. Such poems, like "in dem aberellen, so die blûmen springen" have been easily found by us. 

We are using extremely powerful tools to find these which voynich didn't have. But sure, technically voynich may have read this poem (among many many other poems containing aberel, abrel, abril etc) and chosen this form instead of the other forms. So I admit that there isn't actually any way for me to argue against what you are saying, which is fine 

If you can find a "jollet", "iollet" or even a "joillet" (that isn't a smudged juillet) from later printed works, you would certainly have me questioning things, as it would constitute finding something that has never been found in any manuscript.

And as Mauro reminds me, what of octembre? The fact that its usage in manuscripts seems to have peaked at around the same time as the dating of the parchment is extremely coincidental imo. The chances that Voynich would find a rare octembre in an 19th century print and happen to have chosen a form that matches the dating would be really lucky. Alternatively, he researched which forms to use in order to be accurate, but then chose to split into two languages.