A Quantitative Confirmation of the Currier Language Distinction

We present a quantitative analysis of character-pair substitution ratios in the Voynich manuscript, testing whether Currier's A/B language distinction (1976) reflects a genuine structural property of the text. A Beta-Binomial mixture model applied to raw character counts without access to labels recovers the Currier split with ARI = 0.383.

A supervised Beta-Binomial classifier trained on a subset of folios predicts the A/B identity of held-out folios at 89.2% accuracy. The character pairs separate into three functional regimes that constrain any theory of the Voynich writing system.