As an editor who works primarily for the Canadian market, I am amazed at all the subtle differences that separate Canadian and American English, and how difficult it can be to keep track of them. Even the work of seasoned Canadian authors often contains inconsistent spellings of certain words. In fact, some Canadian readers may be unaware of all the differences between American and Canadian English.
First off, Canadian English is not what was once called "the Queen’s English," using spelling forms that are standard in the United Kingdom. Instead, Canadian English is a combination of British and American forms, and it can be tricky to remember which words take the American form, and which take the British. This is a real challenge when the same word takes different forms depending on what it’s doing in the sentence: fulfil, fulfilling, fulfilment is one example of this.
Related: Want an expert to Canadianize (or Americanize) your spelling? We can help!
Examples of Canadian English words and their American counterparts can be found in the following categories: -our/-or; -re/-er; -yse/-yze; -ll/-l; -c-/-s- plus endings; silent -e- plus suffix; and diphthongs. For instance, Canadians use colour for color, centre rather than center (or the tricky manoeuvre for maneuver, which always makes me stop and think!), and analyse for analyze. We also use enrol instead of enroll, but distill always has two ls. And just to be confusing, we spell install with two ls but instalment with only one.
In Canada, a hockey team has good defence (not defense), but your position may not be defensible regardless of which side of the border you are on. You can practise (verb) law in your law practice (noun) in Vancouver, but not without a licence (noun). Judgment (no e) may be rendered, but you may not receive any acknowledgement (with an e) for it. You won’t have to pay for anaesthetic under Canadian health care, or to see an orthopaedic surgeon, though someone in a hurry might travel to see an orthopedic surgeon in the States.
This is why, for any project, one of the first things a copy editor will want to know is which dictionary to use to maintain spelling consistency. The two reference works I use most frequently for Canadian projects are the Concise Oxford English Dictionary, considered the best desktop reference for British English, and the Canadian Oxford Dictionary, the first authoritative dictionary of unique Canadian English. Another invaluable resource is Editing Canadian English, 2nd Edition, which lists Canadian spelling forms, hyphenation rules, capitalization, punctuation, and French use in English documents.
And what would rules be without exceptions? Rigor, squalor, and tremor are spelled that way regardless of where your readers are located, as are genre, massacre, and mediocre. Your poodle could be kidnapped in Toronto or New York, and sheep are woolly in every country. Although analyse is spelled with an -se, words ending in -ze, like emphasize and realize are spelled using -z. The list goes on…