Why do Americans spell words like "theatre" with "er" instead of "re" at the end?

@Patriot96 But he wasn't American, he was English.

@BijouPleasurette It was Webster and his misguided belief that it was possible to spell English in such a way that everyone would pronounce words the same way. Such people crop up with depressing regularity.

@ninalanyon Does Webster's Dictionary include etymology? That seems an unknown quantity in the American dialect.

Hence, a pedofile actually has an unhealthy obsession with feet, not children (that would be paedophile); and the US geologists who ordered the world to spells the Cainozoic (a particular geological time span) Cenozoic, reversed its meaning from full to devoid, of life!

It does not explain another American trait though: "simplifying" some words by their spellings, but complicating others needlessly. Hence even axing central syllables (e.g. labor-tory, alumin-um) but adding clumsy extensions elsewhere.

E.g., inspiring to inspira-tional, so three to six syllables - and odder still, burgle to [i]burglarise (probably "burglarize").

@ArishMell If we have to have burglarise it should be spelled with an s because the root word is not derived from Greek.

@ninalanyon Good point! I think Americans go by pronunciation not origins.