Lets take a tour around how language works! :D
Its incredible how language morphs and changes in different cultures over time, because it really reminds you how organic it is. In American English, the verb cancel is usually inflected as canceled and canceling—with one l. This is not a rule globally, however, and exceptions are easily found. In varieties of English from outside the U.S., including Canadian, British, and Australian English; cancelled and cancelling are the preferred spellings. Some claim this is an "Irregularity" or is simply "Incorrect" usage by those "Ignorant Americans" But, let's investigate rationally with respect to how language works.
First, lets examine some of the rules currently found in English. The doubling rule says that IF you add a vowel suffix (-ed) to a word that ends in a single vowel, single consonant, you double the final letter (so long as it is not an X or W) UNLESS that syllable is unstressed.
Cancel and
Travel have a final unstressed syllable (similar to suffer/suffering, refer/reference) so by this rule the
L should not be doubled, as it is not in American orthographic practice.
HOWEVER, the other systems take their cue from the British orthographic practice, which actually does introduce another rule, which is that if the last letter of the base or stem is an L, you double regardless of stress (as in fueled in America, fuelled elsewhere). For whatever historic reason, American orthographers have dropped this rule from their spellings. There are many other such divergences, such as -re vs -er as in centre/center and -ise vs. -ize as in organise/organize.
Does that mean that the american spelling is simply "Wrong" and that, well,
English English is the ultimate know all and say all for what is -
currently- correct or not? Of course not. That is just biased babble and is forgetting the very history of how English (or any language for that matter) was formed!
English has never been its own language. Many other established languages themselves borrow from a myriad of sources, and English English is quite old. It originated as a Germanic language, and sounded far more like Dutch in its past, before the Normans took the British Isles and introduced French into the language. English is the result of the union between a Germanic and Latinate language, a fairly unique blend, and the United States is simply continuing this fascinating organic trend -that all languages constantly follow- in just a different geographic location separated by a major ocean. Stated shortly, what appears to be "exceptions" to the English language is really just the development of different sets of rules by Geographic Isolation. And because of this, American English is its own -completely legitimate- form of English.
As the Ngram below shows, American English has only recently adopted the one-l spellings of canceled, canceling, etc., and the change is not fully ingrained in the American language. It's very interesting, however, because this "Canceled" vs. "Cancelled" problem stems from the longstanding trend in American English toward single-l spellings of participles formed from verbs ending in "-el." It's actually surprising that it took so long for "cancel" to change this way, as it happened to other "-el" words about a century ago. Surprisingly, in the past few years the spelling of "Cancelled" is making a rebound though.
Anyways, what do you guys think on this topic of language? I, for one, am very interested in how it organically develops... Lol.
NGRAM BY GOOGLE:
http://i.imgur.com/cYHYU.png