The German Language

[Regina]

Then again, as a writer, I like using archaic English words such as “fortnight.”

Interesting you call "fortnight" archaic, that word is still commonly used in The UK

You can see the beginnings of language shift have happened in the differences between British and American English. A few centuries of relative separation has already made some differences in the words we use. It just hasn't happened at the same speed that Medieval English and German emerged, because we haven't been as isolated from eachother.

It'll probably stop happening altogether in the modern world, because we have international media and constant contact between different nationalities now. British and American English have been getting more similar in the last few decades, not less. The same can probably be said for Iberian Spanish and forms of Latin American Spanish.