This might be a bit of a obscure topic, but I was wondering if there were any identifiable patterns that we can use in alt-history to determine how innovative language or dialect in a specific region would be in terms of phonological, grammatical and other changes related to linguistics.
For example there is the obvious example of foreign linguistic rule which would bring loanwords and some influence, but other than that what are the factors that also play a role? For example we have Sardinia and France, how would one go about reversing the 2 in terms of innovative-ness and conservative-ness?