An Artificial Construction

[oshfdk]

For the core, you could use the vowel that has a tone diacritic. 

(Edit: I've updated the image to include all pairs, I think I misread the description of the computation by dashstofsk, this doesn't affect the conclusions.)

   

Here it is. I repeated @dashstofsk computation as described in the original post. This is what I would expect from a natural language - a lot of underrepresented combinations (and a few hugely overrepresented). Nothing like the Voynich MS chart for which the upper left corner mostly consists of numbers close to one.

I suspect that no natural language would allow for any fixed B independently picking A and C according to their general frequency to produce the distribution of ABC as seen in the Voynich MS, no matter what A, B and C correspond to - characters, words or syllables.

Now that I have the code in place, I can repeat the test for any text and any kind of B, but I expect the result to be largely the same.