Evidence for 2 rules linking words in Herbal A->B

[MarcoP]

I computed some basic stats for Herbal A Early and Herbal B, based on the ZL transliteration, ignoring uncertain spaces.
Benches and benched gallows were treated as single characters.
The colored column shows if the item is more frequent in A (red) or B (green).
As always, it’s possible I made errors along the way.


Characters:
   
This shows that the five most frequent glyphs vary considerably.

• 'y' is the most stable of the five.
  
• 'o' and 'ch' are considerably more frequent in HA.
  
• 'a' and 'd' are considerably more frequent in HB. For 'd', the thing can easily be understood on the basis of the frequent -edy suffix in B.
  
• B:a increases but B:n decreases, so the additional 'a's do not occur as -ain -aiin.
  

Given that the three "circles" o,a,y are often regarded as related, one can imagine that there is some kind of re-distribution inside this class of glyphs (A:o turning into B:a,y).

It's interesting that the frequency of 'q' doesn't change: the class of q-words could be a relatively approachable subset for an A/B mapping.

Bigrams:
   
The increase of ‘dy’ in B is again fully expected.
I highlighted a few bigrams whose changes I speculate that might be connected:

• The frequent ol/or bigrams in A might “become” al/ar bigrams in B (see char stats above).
  
• sho/cho in A might partially “become” she/che in B. But cho drops by 5% while che only increases by 1.5% and a lot of ‘ch’ disappear in B (see char stats), so there could be cases where ‘ch’ is dropped or changed into something else.
  

Words:
   
I find word results hard to read: word stats appear to be entirely different in the two text samples. Honestly, this table makes me think that the task of an HA/HB mapping is terribly hard.

Something I want to point out is that both ‘chor’ and ‘shor’ decrease from A to B, while both ‘or’ and ‘ar’ increase, so it could be that the initial bench is sometimes dropped and initial o- sometimes turns into a-.
The two most frequent words in A, daiin and chol, have dramatic drops. A classical and plausible idea is that aiin in B partly corresponds to daiin in A, but the difference for daiin is -3% of all words, while the increase in aiin is only +1%, so aiin can only explain a minor part of what happens with daiin.
The idea that A:qokchy might become B:qokedy (put forward in post #1) appears to be a plausible one and explains some of the loss of A:ch.