In saying that, you are aware that #AmericanEnglish is, in many aspects, more original than British English b/c Noah Webster was so far ahead in his time in preparing his famous dictionary.
Also, have you had the change to place a full printed edition of Webster's next to the Oxford's Dictionary?
Even discounting the many neologisms, Webster has more than 1 million words, many more than Oxford's Dictionary or the German Duden.