A lot of the differences come from the varying rates of development of the language in common use. In North America the advancement in development of the language was impacted and stagnated to a certain extent by the massive influx of non-english speakers during the mid to late 1800's.

Long, long ago I can remember being told that in the very early 1900's (1905 or 1911) there was a debate in the House of Representatives regarding the adoption of German in place of English as the official language of the US. The motion was only narrowly defeated (something like 12 votes). Now if that is correct, that might have made a bit of a difference to the history of the 20th Century.