[split] Does Voynichese evolve from A to B?

[nablator]

In the case of the copying errors, each page with the bad copies are offset randomly from the original. In the case of the information preserving edits, all the offsets are in the same direction. 

Latin abbreviation can be perfectly systematic (as in: apply a set of rules strictly) or more random (as in: inconsistent choices of what is abbreviated on each line and how). There was always a balance between random and systematic. By the end of the 15th century abbreviation was only an expedient, used sparingly to fit words inside a line without cutting a syllable in two.

The rules and preferences evolved during centuries, they can be dated, but not precisely because the copyist may have preserved some of the source's abbreviation style and some copies used old-fashioned ways to abbreviate words, almost extinct in their own century. However, in most cases, the scribes re-abbreviated the text entirely using their own preferences and choices: each copy of the same source material differs even when the copies are not several decades apart, which is very helpful when trying to figure out difficult abbreviations. So a composite manuscript can have several different abbreviation styles, causing a drift in statistics.