I couldn't resist: The Voynich Vowels

OK, I didn't mean to get started down this route because I'm a little overworked, but I ran my contextual distance analysis on the Voynich graphemes (in EVA transcription).  Based on that, here is my best guess at the Voynich vowels.

The following image shows a map of the similarity of the graphemes in the Voynich Manuscript.  Like the King James genesis, we have a small island of five graphemes which occur with the word boundary (#).  I will call these the *vowels (note the asterisk, which is my caveat that this is all hypothetical).

The *vowels, in EVA transcription, are the letters z, t, k, f and p.  The Voynich graphemes represented here are:

There is an obvious graphemic similarity here:  The tall, loopy letters are all *vowels, as is the z, which might be called a small, loopy letter.

Interestingly, the closest contextual similarities here are between the graphemes that look the most similar:

sim(t, k) = 0.88
sim(f, p) = 0.87

By contrast, the strongest similarities between any two vowels in Latin is sim(e, i) = 0.77, while in English it is sim(a, o) = 0.59.

If the *vowels are indeed the Voynich vowels, then I propose that we are looking at a script with only three vowels, and the EVA [t,k] and [f,p] are merely graphemic variants of each other.

Is it possible that the underlying orthography is based on something like the way Hebrew is used to write Yiddish, using the [א,ו,י] to represent vowels?

In fact, I'll go a step further, just so I can claim credit if this turns out to be true:  Given my earlier feeling that this is a polyglot or macaronic text, is it possible that the underlying text is in Hebrew and Yiddish (or another language of the Jewish diaspora, like Ladino)?