"New" spellings
(This post was rejected - I think that must have been a mistake)
"color, center, aluminum and other new versions of old words"
That's an oversimplification. According to the OED, although "centre" was the form in which it came from Norman French, by Shakespeare's time "center" was prevalent in Britain, and was only replaced by "centre" as a result of Johnson's dictionary. "Aluminium" and "aluminum" were both common in the USA for much of the 19th century; the decline of "aluminium" was assured by a report by the American Chemical Society which recommended "aluminum" around 1890. It also recommended "sulfur"; but was less successful with "iodin".