The Voynich Manuscript’s positional entropy collapse: comparative evidence from languages and ciphers

The Voynich Manuscript exhibits unusually low conditional character entropy and rigid positional constraints that have resisted explanation within linguistic frameworks for more than a century. In this study, I apply a leakage-free, folio-segmented, character-level analysis to the Voynich Manuscript and to a set of natural-language, constructed-language, and cipher control corpora. The analysis measures bigram and trigram bits per character, the marginal gain from higher-order context (ΔBPC), positional cross-entropy within words, and local lexical overlap under minimal edit distance. All experiments employ strict recto–verso train–test separation, transcription-layer isolation, and identical preprocessing across corpora. The results show that Voynichese exhibits a pronounced collapse of medial positional entropy and a consistently small ΔBPC. These properties persist across manuscript sections and transcription layers and are not reproduced by natural or constructed languages under identical conditions. Applying the same analysis to a verbose substitution cipher derived from a Latin source text demonstrates that this cipher reproduces the Voynich statistical profile with high fidelity. Shuffle controls confirm that this profile is destroyed when internal adjacency is randomized, indicating structured generation rather than sampling artifacts.