The most frequent transitions from particular glyphs to other individual glyphs are very different in Currier A and Currier B. I'm not sure whether this way of looking at differences between the two "languages" has any advantages over (say) the study of bigram frequencies. But it's at least a different way.
So, for example, it's common to observe that [ed] is common in Currier B but almost nonexistent in Currier A. With transitional probability statistics (limited to "paragraphic" text and ignoring spaces), this comes out instead as:
Currier A: e>o (51.92%), e>y (28.65%)....
Currier B: e>d (47.36%); e>y (19.85%)....
That is, in Currier A, any given token of [e] (as distinct from [ee], [eee], etc.) has a 51.92% probability of being followed by [o], while in Currier B, it has a 47.36% probability of being followed by [d]; and in both cases, the next-most-probable following glyph other than the "most favored" one is [y]. There are plenty of statistical patterns that these single glyph-to-glyph transitions won't catch, of course, but that's also true of bigram frequency statistics, so I figure these are worth a try.
One question that sometimes comes up is whether Currier A "evolved into" Currier B, and I was curious to see whether calculating transitional probability matrices for individual bifolios (limited again to "paragraphic" text) would suggest any particular sequence of transitional phases.
The most common transitions from [Sh], [d], and [e] seemed to be most reliable for distinguishing A bifolios from B bifolios overall, but some A bifolios diverged further from the typical B profile than others, consistent with a "gradual introduction" of new features. With that idea in mind, here's a tentative evolutionary sequence ("e+" means any quantity of [e]):
Sh>o / d>a / e>y: 1+8, 2+7, 9+16, 11+14, 13, 18+23, 25+32, 27+30, 35+38, 36+37, 42+47, 44+45
Sh>o / d>a / e>o tied with e>y: 10+15, 49+56
Sh>o / d>a / e>o: 3+6, 4+5, 17+24, 19+22, 20+21, 28+29, 51+54, 52+53, 93+96
Sh>e+ / d>a / e>o: 58+65, 87+90, 88+89, 100+101
Sh>e+ / d>y / e>o: 57+66, 99+102
Sh>e+ / d>y / e>d (standard “Currier B”): everything else
I didn't find bifolios with combinations outside this sequence -- for example, a bifolio in which [e] was most often followed by [y] and [Sh] was most often followed by [e+]. So, based just on this possibly sketchy evidence, the most likely sequence of "evolutionary" steps would seem to be:
(1) e>y is overtaken by e>o, after briefly tying with it
(2) Sh>o is overtaken by Sh>e+
(3) d>a is overtaken by d>y
(4) e>o is overtaken by e>d
I haven't tried calculating probabilities separately for different parts of bifolios to see if these statistics are consistent across them. That might be interesting, although the reduced size of the dataset would amplify the statistical noise.
Some other distinctive "most favored" transitions consistently match one of the above combinations. For example, l>k goes with the combination Sh>e+/d>y/e>d.
Other distinctions nearly follow the same sequence, with exceptions clustering around the "borderline" or "transitional" or "intermediary" combinations Sh>o / d>a / e>o and Sh>e+ / d>a / e>o. Thus, for k> and t>:
- k>o, k>ch, t>o, t>ch are all with Sh>o (only exception: tie of t>o with t>e+ on 88+89, in Sh>e+ /d>a /e>o)
- k>a and t>a are with Sh>e+ (only exception = t>a on 51+54, in Sh>o / d>a / e>o)
- t>e+ is with Sh>e+ (only exception: 93+96, in Sh>o / d>a / e>o)
I don't have high hopes of this leading anywhere, but the post has been sitting in my "drafts" folder for long enough that I figured it was time to let it loose.