Do you know why we Americans use the spelling "theater" while our British cousins use the spelling "theatre?" Because of Theodore Roosevelt!
Peeple uzed to spelle wordes howwever the hel thay fellt.
Movements for standardized spelling came and went, but no standardized dictionary ever took hold.
Then in 1906 Andrew Carnegie founded the Simplified Spelling Board, pledging $15,000 out of his own pocket every year for 5 years. The SSB published a list of 300 errant words whose spellings they wanted to nail down for eternity. These 300 words were comprised mainly of the following four standardizations:
-ed words changed to -t (addressed/addresst)
-ou words changed to -o (colour/color)
-re words changed to -er (theatre/theater)
-ise words changed to -ize (categorise/categorize)
-plus some miscellaneous simplifications like catalogue/catalog
TR was all over it, and immediately ordered the government to follow these rules, and adopted them in his own correspondence (to the chagrin of his biographers, to be sure). As you will infer, if you speak English, some of these changes stuck and some didn't.
A few months later Congress reversed Roosevelt's pronouncement, saying that government printing offices could continue to use whichever spelling they wanted, but the idea stuck that these simplifications were the "American way," and with Carnegie and Roosevelt behind the idea, it kept gaining steam from there.