In any language letters are predictable. In a sentence words are predictable if you look at the SVO or VSO etc. word order and grammar.
In Voynichese exactly the same: letters are predictable and word sequences as well.
There are some differences.
Firstly the letters which are predictable must follow predictable paths for all letters, just a few, or none.
There is no language where that happens, however in Voynichese it happens that there are many letters that behave unpredictable, or as you wrote "have exceptions".
Also the word sequences are predictable. However, this is only valid for some words. There still are a huge amount of words that are unpredictable.
That happens when for example it's a poem, a song or a scientific text on a specific subject in normal languages.
Lastly the composition of words is monotonic (or monotone) and that is also very strange.
Even if it is a ciphered text, they still have to follow cipher rules which would still make the composition of words vary more than it does now.
The only explanation I have for that is that a) the cipher works in such a way that the result is a similar composition of words, b) the cipher was wrongly composed and that is reason it can not be deciphered, or c) those words are mainly full of nulls and the repeated letters are just nulls, or d) the letters are highly abbreviated, for example o=oleo, i=item etc. but then the spaces make no sense
In Voynichese exactly the same: letters are predictable and word sequences as well.
There are some differences.
Firstly the letters which are predictable must follow predictable paths for all letters, just a few, or none.
There is no language where that happens, however in Voynichese it happens that there are many letters that behave unpredictable, or as you wrote "have exceptions".
Also the word sequences are predictable. However, this is only valid for some words. There still are a huge amount of words that are unpredictable.
That happens when for example it's a poem, a song or a scientific text on a specific subject in normal languages.
Lastly the composition of words is monotonic (or monotone) and that is also very strange.
Even if it is a ciphered text, they still have to follow cipher rules which would still make the composition of words vary more than it does now.
The only explanation I have for that is that a) the cipher works in such a way that the result is a similar composition of words, b) the cipher was wrongly composed and that is reason it can not be deciphered, or c) those words are mainly full of nulls and the repeated letters are just nulls, or d) the letters are highly abbreviated, for example o=oleo, i=item etc. but then the spaces make no sense