I've no idea how the message about the Dead Sea scrolls attached itself to my name - a joke by the great attractor, I expect.
One scenario which occurred to me and almost simultaneously to an Italian chap (whose name escapes me for the second) is that the manuscript represents the results of efforts which are recorded being made by Poggio Bracciolini to accumulate information about eastern plants. He interviewed various pilgrims but ran into problems. His translators could manage the grammar but had no equivalent in their own language or in Latin for the plant's names. Then, a bit later than the parchment's date (but not much) de' Conti arrived back from years working in the east and had certainly learned the names and virtues of eastern plants during his decades there - at least that was all he talked about according to to the Spaniard he met.
Many eastern languages are tonal or would seem so to a European - like the three positions for 'k' in Arabic.
So it is conceivable that an oral account might be taken down, with spaces left for inserting a sign indicating whether the sound was high, median, low etc. And the informant would fill those out in the fair copy.
From experience, I can assure you that it is possible for someone with a good ear to simply learn an alphabet and then be able to transcribe information dictated to them. They may not end up with perfect orthography, writing n for the formal ng or (to use an example from Japanese), writing 'mas' for the formal 'masu'.
In the imaginary scenario with de' Conti (and any number of other candidates) the script might be a simplified version of an eastern script, affected by their own native habit. A person used to writing Hebrew might square off letters; a person used to writing a European script would omit the line from which Indian scripts hang.
That would explain the interlocking 'hands', the general appearance of a writing not natural but 'drawn', and the fact that we have no other example of similar script extant (at present).
But this is just a scenario, as contra- to the current emphasis on Rugg's theory.
Diane