Engineering your own voynich

[nablator]

Has anyone tried treating "FaiT Kzz" as "This is", the last word "Ka" as "it", "-yun" as "-ing", for example? What would that give?

Yes, there are some frequent patterns that are probably "the", "this" or "then" but I didn't manage to solve the 3 alphabets with such a short sample: there could be as much as 3 different ciphertexts for the same chunk of cleartext (depending on position modulo 3).

Also possible IMHO:
Tiiiig = the (most frequent word in the ciphertext)
Tiiiiz Ti = that

FaiT Kzz is repeated (once) and there it follows Tiiiig.