Cipher or unknown language - historical perspective

[ReneZ]

That's correct. And later, there were also at least three different alphabets created from scratch for Albanian, one of them surviving in, I believe, only one single manuscript. So the idea that the Voynich Manuscript can't be a lost language and writing system because we only have one single manuscript, is refuted by that very above-mentioned Albanian manuscript.

That may also be correct, but we still have the problem that the Voynichese text cannot be explained as a rendition of a still-known language using an otherwise unknown alphabet. While Albanian is certainly an exceptional (for lack of a better word) language, it is still well known nowadays.