General rules for Canadian spelling
The "rules" for Canadian spelling are not as cut and dried as you might think. There are some regional variations, and differences of opinion exist among editors. The government style guide says that editors should consult the Gage Canadian Dictionary and go with the word used first, an unsatisfactory solution compounded by the unsatisfactory nature of Gage. To get a better sense of what the norm is, in 1984 the Freelance Editors' Association of Canada (now called the Editors' Association of Canada) surveyed publishers, academics, PR people, editors and writers about their spelling preferences. Here's what FEAC found out.
COLOUR OR COLOR? Three quarters of the respondents preferred -our endings. (See below.)
CENTRE OR CENTER? Eighty-nine per cent went with traditional -re endings such as centre and theatre .
CIGARETTE OR CIGARET? A similar proportion as above preferred cauldron to caldron and preferred the long forms of axe, catalogue, cigarette, moustache and omelette, but program won out over programme.
DEFENCE OR DEFENSE? Four fifths of the sample preferred -ce over -se in nouns such as defence, practice and pretence, but let -se stand when such words were used as verbs, such as to practise the piano lesson.
AESTHETIC OR ESTHETIC? Three quarters used the diphthong (ae or oe) in such words as aesthetic, archaeology and manoeuvre, but those polled split on medieval.
ORGANIZE OR ORGANISE? Canadian editors rejected the British -ise endings, such as organise, preferring -ize endings. (This page, in fact, was born when several of our clients ran our work through MS Word spellers, and then complained about "spelling mistakes" like organization.)
CHEQUE OR CHECK? Many homonyms are given different spellings to convey different meanings, including mould/mold, cheque/check and racquet/racket. A cheque, for example, is something you use to pay for a dipstick, which you can use to check your oil.
ENROLL OR ENROL? Majorities of up to 90 per cent liked the double L in such words as enroll, fulfill, install, marvelled, marvellous, signalled, skillful, traveller and woollen.
This brings us to a quirk of Canadian spelling, in that we have our own way of doubling letters before adding suffixes. If a word ends in a single vowel followed by a single consonant, that consonant is usually doubled for most suffixes. "I am biased since I helped myself to local cuisine while travelling in Greece." This rule is a little different from the American rule, which forbids the consonant doubling unless the word has one syllable, or stresses the last syllable.
Here are a few spelling distinctions that FEAC didn't look into.
ADVISER OR ADVISOR? We'd go with advisor.
COMPLEAT OR COMPLETE? Canadian spelling is complete. Use of compleat tends to be reserved for affectation.
CO-ORDINATE OR COORDINATE? Canadians like hyphens after co. Co-ordinate how you co-operate. The government style often differs, however.
GRAY OR GREY? Canadian spelling is grey.
SCEPTICAL OR SKEPTICAL? Canadian spelling is with a C, although this is fading with time. Many newspapers use K.
SULFUR OR SULPHUR? Canadians prefer sulphur, but the scientific standard is sulfur.