I’ve been playing around with the Google Books Ngram Viewer amidst grading and procrastinating from grading. Here are a few interesting results (along with the corpus and date range for each). Any others you can find?
soda vs. pop, American English, 1900-2008
sneaked vs. snuck, English One Million, 1800-2008
douche, English One Million, 1800-2008
milliard, British English, 1940-2008
encyclopedia vs. encyclopaedia, American English, 1800-2008 vs. encyclopedia vs. encyclopaedia, British English, 1800-2008