Do you believe Voynichese is a substitution code for a natural language?

[Wladimir D]

I don't get it  What is mat? Russian slang?

David, what do you say when you hit your finger with  a hammer?
According to the law, words with roots refer to "mate", which describe: 1 / the male sexual organ.
2 / female reproductive organ.
For their description in open sources use the Latin terms - phallus and vagina.
3 / the process of copulation.
4 / the name of a woman with low social responsibility (as our president calls them )
If a Russian football player is heavily beaten from behind by footsteps, the whole stadium hears the word - бл *дь . If it was a footballer from another Eastern European country, you would have heard - kur * a.
In the Czech language, the word čur*k is also a “mat”, but in Russian it is not “mat”, although from this root "čur" (чур - stump)comes  an offensive name  from Middle Asians. 
With the help of the roots of the Russian "mat" you can describe a lot of concepts.
Nouns - a man, a woman, a girl, any person, the end (of the working day), a simple matter, any subject, of known and unknown purpose, ...
Adjectives - good, excellent, bad, very bad, beautiful, disgusting, ...
Verbs - to walk, beat, walk, steal, talk, lie, go crazy ...
But most often in colloquial speech these words are used as introduction words (as we say " to link words", in place of a comma). In this case, these are zero words that do not require translation.