All across North America, most French language courses—practically all of them in fact—emphasize a way of speaking that is not highly relevant in North-American cultural contexts.
In contrast, imagine yourself as a Québécois having to learn English due to an upcoming relocation to, say… Texas. Wouldn't it seem just a bit strange to be taught to pronounce the language with a British accent, and to learn words like “lorry,” “boot,” and “bonnet,” when you could be learning “truck,” “trunk,” and “hood” instead? In fact, most Québécois who speak English have learned either a Canadian or American variety. Doesn't it make sense to learn the language of your destination or your target audience or your closest neighbors?
That's why it makes no sense to teach (or learn) “myrtille” for blueberry if you are in a North-American classroom. Not because “myrtille” is bad or incorrect, but because we live in North America and “myrtille” is not a North-American word. We say “bleuet” instead! In the case of “bleuet,” we're not talking about a colloquialism or a slang term. It IS the word here, and you can plainly see this on any bilingual label of a box of blueberries here in this hemisphere, whether the box originates from Québec, Michigan, or Chili, South America. They are all labeled BLEUETS. Even folks in Guadeloupe and Martinique (two French départements in the Caribbean) are getting their blueberries with BLEUETS on the label. So, why would you not learn this word?
The list of vocabulary differences doesn't end with blueberries. The Parisian lunch is our breakfast, (déjeuner), our “dinner” (dîner) is normally eaten between 11:00 a.m. and 1:00 p.m., and our use of the word “souper” is not limited to late night outings the way it is in Paris. One small detail: The words “déjeuner,” “dîner,” and “souper” reflect an older (more conservative) usage than the “modern Parisian” equivalents: petit déjeuner, déjeuner, and dîner, and these “Canadian” terms are also used in Belgium and Switzerland. Do the vocabulary differences end there? No, that's just the beginning.
I can almost guarantee you that most people learn “pain perdu” for French toast (a perfectly logical term) in French class, but we don't say “pain perdu” in Québec. Our term for that very same thing is “pain doré” (another perfectly logical term).
And does anybody know what “une valise” is in Québec? If you guessed “suitcase,” you're right. However, it's also what most other French speakers would call “un coffre,” which is the "trunk" of your car! If someone from Quebec wants you to put something in the trunk, you are more likely to hear, “Mets ça dans la valise!” instead of “Mets ça dans le coffre!” The word “coffre” isn't wrong, but “valise” is much more common on this side of the Atlantic.
By now you must be wondering: “Is the Canadian French language really that different from the Parisian French language?” My answer to that question is, well… yes and no. The language is fundamentally the same, and aside from local words and expressions, there are few differences between formally written Canadian French and formally written Parisian French. The spoken language is markedly different, however, especially in informal situations. Both Canadian French and Parisian French use a lot of slang and far too many anglicisms, especially the Parisians. Since the slang and anglicisms used on each side of the Atlantic vary widely, this can oftentimes make informal communication between the French and French-Canadians rather—shall we say—“interesting.”
I'll end these comments with a brief story from a good friend of mine. I think it illustrates the “Know-your-audience!” principle quite well and why North-American French should be emphasized in North-American classrooms.
Pierre, a Québécois, was at a social gathering where the dominant language of the evening was Canadian French. There was also present there a very sweet woman from Paris with her two kids. In addition, there was a smart, but very naïve Anglophone woman there whose schoolbook French was very European in nature. As the Parisian mother and her kids were leaving, this Anglophone said, very sweetly, “Au revoir, mes gosses!” a perfectly acceptable statement to a Parisian. “Au revoir, mes enfants!” would have been a much better choice, however, given the crowd overhearing her good-bye. Why?
Anyone who knows Pierre, knows he likes to tease, and tease he did! But, this Anglophone female friend of his never got his “joke,” because she didn't know that in Québec, “gosses” doesn't mean “kids.” It means “balls,” “nuts,” (testicles) and so on. As a result, to a Québécois like Pierre, the sound of a woman saying “Au revoir, mes gosses!” was very funny indeed! (Was there something he didn’t know about his friend? Was there a surgical procedure involved here? Not that it would have mattered, but…)
She didn't have a clue why he was teasing her, and he, not wanting to seriously embarrass her in front of so many people, didn't explain anything at that time. Looking back, Pierre says that he probably should have. She's married to a Québécois now, and it’s probably a safe assumption that by now she’s been enlightened.