Can you ask about anything easier? lol
I think first we would need to invent a scale to measure language change, and be able to compare the changes in different languages. I'm guessing that it borders with something impossible.
Secondly, we would need to separate normal evolutionary change of a language from forced changes, like exposure to second language.
Thirdly, we are lacking enough historic records for many languages that you mentioned.
Lastly, the language of educated elite (written records that survived) was different in some cases from language of commoners.