British English may have come first, but around the world, the American way of spelling is now far more popular.
A recent examination of the English language shows that publications now largely use the American version swapping words like “centre” for “center” after the 1880s. To get data, researchers used Google's Ngram Viewer to analyze the words found in all English-language publications from 1800 to 2000. Entering a word into the viewer will show how frequently it occurs within the massive corpus(语料库)of books around the world.
According to the data, this shift was further strengthened around World War I. Since then, English-language publications have preferred “gray” and “flavor” instead of “grey” and “flavour”. The American spelling has continued to grow over the years, with “liter” passing “liter” around 1900, and “center” becoming the more common choice over “centre” in 1913. “1913 marked a turning point in British spelling, as the American alternative became more frequently used in literature,” the post explains, in regard to “center”. This was just a year before the beginning of World War I, which many views as a key period in America's rise to superpower status.
Though this switched again between 1920s and the late 1930s, the American, spelling took over for good around 1940, during which time the spelling “airplane” shifted dramatically over “aeroplane”.
Ever since the middle of the 19th century, even the British Isles have slowly rejected the old spelling. The future is gray for British English.