Guns, Germs and Steel in cultural terms?

Still, the guns (or in general, weapons) part was important, centuries of in practice isolation eventually gives you a different language, until an invader wipes your population, culture and language because it wants more resources and new territories for expansion over slaves that can't understand them (or germs finishing the work anyway).

Low granularity on data over long periods doesn't help there, with history, written word and then mass printing not only you get better records, but also you get a pressure for normalization and loss of language diversity.