Is Voynich a right-to-left script?

[magnesium]

In the case of the Voynich, I think having a lower perplexity in the RTL direction is not really meaningful. Perplexity, which is directly related to entropy, measures how surprised the model is when it sees the actual next character (or word). We already know that the Voynich has unusually low entropy for bigrams compared to natural languages. So, in my opinion, a slightly lower entropy or perplexity in the RTL direction doesn’t add much insight. In fact, it might even be harder to explain why the text would have an even lower entropy than it already does.

One potentially useful test would be to assess the perplexity of a Naibbe ciphertext in LTR and RTL directions. In this case, the cipher is very consciously mimicking the VMS word grammar (the driver of the VMS’s entropy) while encrypting a left-to-right Latin or Italian plaintext.