Why not positional variation?

[Torsten]

A codebook scenario could work, since TTR stats are a bit more normal. In a 1 to 1 code though, we would still expect to see common phrases pop up (like "nomen herba est" or something like that). If I recall correctly, those are not obviously present.

Another challenge for the codebook theory is explaining the shift from Currier A to Currier B. To account for this change, one would have to assume the use of different codebooks for different sections of the text. Additionally, since word types typical of Currier A also appear in Currier B, but not vice versa, it would require continuously adding new code words. Furthermore, in natural languages, frequent words—such as function words like conjunctions and articles—are evenly distributed throughout a text. This would necessitate using multiple code words for each function word. But what reason would someone in the Middle Ages have to adopt such a laborious method for encoding a whole book?

If we assume that the text contains a hidden message, the steganography hypothesis would provide a more plausible explanation. In theory, any text could be used to conceal a hidden message. For example, one could track the frequency of specific glyphs within a section of text, such as counting the number of curved glyphs between two gallows or tallying the occurrences of a glyph like EVA-[i] within a line. However, the main drawback of this approach is that, even in an entire book of text, it would only be possible to hide a relatively short message.