The vowel exchange "a" to "o"

[dashstofsk]

the question is whether anyone has already looked into this topic more intensively?

I have in the past looked into this for many character pairs. The matrices of affinities will give you some clues as to which characters can possibly be interchanged. Attached are lists from language A of the most frequency a and o words and alongside the frequency of words formed by the exchange. I can't see much that is significant in this particular exchange.