Interesting premise, but be careful with the linear thinking here. As a counter example, Icelandic didn't change as much as English in the past 200 years. For English, one would probably need to look even further back in time than 200 years. Change in language use is somewhat related to the number and diversity of speakers and the number and diversity of english speakers didn't grow linearly in the past 200 years and probably won't grow linearly in the next 200 years.