Comment by mellow_observer

I don't think that's likely possible. How would you determine the score? Where would you get your corpus of medieval words? How would you deal with the insane computational complexity?

Pecularities in Voynich also suggest that one to one word mappings are very unlikely to result in well described languages. For instance there's cases of repeated word sequences you don't really see in regular text. There's a lack of extremely common words that you would expect would be neccessary for a word based structured grammar, there's signs that there's at least two 'languages', character distributions within words don't match any known language, etc.

If there still is a real unencoded language in here, it's likely to be entirely different from any known language.