Just fyi there are already some answers to this question that you can read in the FAQ.

https://www.reddit.com/r/AskHistorians/wiki/language#wiki_american_and_british_spelling

There were ( and continue to be) different driving personalities that shape national languages . In this U.S. case there was Daniel Webster , a typically underrated man, that was working to make American language through his views on efficient and more phonetically accurate revisions.

There is a fun couple chapter regarding this in 'Between you & me, confessions of a comma queen ' of Mary Norris