One of the mysteries of the VM is, that it is possible to transcribe it in such a manner that it is possible to pronounce the resulting text almost fluently. (The most common of these transcription schemes is EVA, but it wouldn’t be too hard to come up with others.)
This “speakability” is amazing because we can be pretty much sure*), that the VM is not enciphered with a simple substitution cipher (where one would, eg, replace all occurences of the letter “A” with “$”, and “B” with “@” and so on). Rather, some mechanism has been applied which transformed (substituted, transposed, fragmented, a combination or all of those…) the plaintext into the familiar VM words. (From the regularity of VM word structure, we can be sure*) that there were some kinds of “rules” or syntax applied in composing them.)
Which conclusions do we draw from this?
“Speakability” means something like having two groups of letters, the vowels and the consonants, and not-too-long sequences of vowels alternate with similar sequences of consonants. Long consonant strings at one word’s end may meet long consonant strings at the next word’s beginning.
“Speakability” of the underlying plaintext must have been lost in the enciphering process, so the observed “speakability” must have been introduced in the same process.
What kind of encipherment would do that?
(I know it’s not truly a case of onomatopoeia, but I liked the sound of that word.)
*) as far as anything is “sure” with the VM…