Ah, but that's because we're culturally imperialistic to the point of vigilante lynchings. There are positive inducements to become fluent in English--there are also negative ones, never mind the trouble we have trying to ensconce them in written law.
This Canada on the other hand starts out with the French leg of bilingualism greatly strengthened, both in sheer numbers by the immigration of the refugees from Republican France, then because these refugees included classes of subject (was going to say "citizens," but that would be a misstep considering the sentiments of these former loyal subjects of the Bourbons now taking refuge under the British crown) who are much higher up the social ladder than OTL's inherited habitants, voyageurs, and metís; the merchants and monseigneurs who settle among the old Quebecois raise the esteem of the francophone community in general, and inspire the old settlers to higher ambitions. Thus, once they secure themselves in the first war with the Americans all business in Canada goes forward on a bilingual basis from the get-go.
Or rather trilingual--or really very polylingual, with the third language--the Native American creole formed from many Native languages--melding out of the press of Protectorate business eventually.
So, what's a fourth and fifth regionally dominant language? Spanish being fourth, whatever dialect of German the Bavarian-derived establishment of Tejas favors being a fifth.
Given this Alt-Canada's foundational experience with translating all business back and forth between several languages I am not at all sure that any centrifugal influence is caused merely by the presence of yet more languages. Other clashes that happen to correlate to some particular linguistic group--such as Rio Bravo people (what is the correct term? Rio Bravan? Rio Bravano?) insisting on calling their subsection a "Republic" for instance--might be a much more serious matter leading to secession than the fact that they happen to speak Spanish.
A conceivable strength of a polylingual polity is that within blocks of territory dominated by one linguistic and cultural tradition, you can have settlements that are colonies of some other tradition. Consider that in addition to French and English speaking settlement in Louisiana, Tejas, Rio Bravo, and the California territory acquired at the peace table, there are contingents of Indian (ie South Asian, to distinguish from Native American), Portuguese, and I forget who all else--West Indian this time too? African troops under the Portuguese or Spanish banner? German mercenaries? I recall some Hawaiians came in with the East Indians too...--a whole bunch of distinct ethnic troop types. Heck, the Irish troops probably don't consider themselves just another dialect of English-speakers--with their brand new shiny subkingdom they will definitely hold themselves separate. So you have all these people settling here and there, probably mainly in Louisiana and the new southern regions though the Irish might settle much more in the north.
So there won't be completely solid blocs of any linguistic-cultural composition anywhere, especially bearing in mind that this Alt-Canada is far more respectful of Native American groups than the USA ever was and even better than OTL Canada in this respect, so the native tribes will probably have their territories de facto contracted but still solidly theirs in some bastion, and their people will be mingled scattered in their former ranges but with political protection based on their people's treaties with the Canadian over-authority.
Now this might turn into a very ugly situation indeed, if this greater Canada does break up in an earthquake of linguistic-based nationalism. It's pretty much the same mess Austria-Hungary turned into, with enclaves of just about every other nationality within the nominal territories of each major nationality it split up into, and generations of irredentism and ethnic "cleansing" following and still going on their bloody poisonous path into our day.
If on the other hand the overarching imperial order is seen as livable and beneficial by all its subjects; if members who are a tiny and easily overwhelmed yet distinct minority in one region are backed up both by the fact that elsewhere in the empire they are the majority and a general imperial policy of backing the rights and dignity of all groups who are loyal and helpful--then we instead have a vast, polylingual composite supersociety, with its many parts strengthening it rather than tearing it apart. Centrifugal secession is not an appealing option when each separated part would have to deal with a polyglot motley crew of minorities; at best each separated substate must adopt the same multiethnic policy the superstate has already developed; history teaches us of course that much uglier "solutions" will occur to the chauvinistic elements of each separate majority.
Separatism would be appealing only if the super-state fails in its mission of orchestrating the many parts into one whole.
I was quite disappointed to learn I had gotten confused and misread William's role; I had thought he would straightforwardly become King of Canada. It is a bit confusing and sad to me he doesn't, but the guy I think he is could still play much the crucial role I imagined for him. I had him cast as the Arthur of his romantic Round Table of Canada but maybe he is going to be just as happy as a humbler Lancelot (one however decently married to his Guinevere!) A knight-errant with a roving commission to cobble together a unity of shared loyalty among very diverse peoples who remain distinct and yet Canadian. He isn't king; this gives the dynasty he splits off of plausible deniability in his renegade Catholicism which the ruling house stays clean of--but he is passionately loyal to his family and the greater British Empire it symbolizes, while also passionate in his new Catholicism which for him is the romantic embrace of colorful other cultures--Canadien, Metis, Louisianien, now the Spanish Rio Bravanos, the Catholic-German Bavarians of Tejas, California and its Latino contingent of settlers. If I read the man right, he will also respect non-Christians such as the East Indians and those Native peoples who choose not to adopt some Christian denomination as yet. I can see him roving up and down the broad new Canadian claims, putting out fires with charm, learning language after language (Spanish is after all not too far from Portuguese and the Latin I'm sure he is brushing up on; the Native languages are a bigger leap but the more languages one learns the easier the next one is and he'd have found ample reason and opportunity to negotiate with American Indians of the Protectorate in the war-preparation months and now during the war).
So I look forward to seeing more of Duke William Ramsey, agent-errant.
Now, if he turns out to be less of a diplomatic genius than I give him credit for, or gets tragically killed off in the endgame of this war with the Yankees or some more inglorious fight down the line, I will be personally sad. But I don't think this paragon of romanticized collaborative imperialism I have imagined is out of line with the Canada that has been established thus far. Perhaps with less dash and sentiment, and more rough spots, I do think this sort of social balance of power in the service of a mutually beneficial common good has already been encoded in the social genes of the BNA system that has evolved already. At this time, the common good appears to be mainly a matter of containing Yankee imperialism and irredentism; it might seem that if the USA does collapse, split up or resign itself to isolationism that the Canadian conglomerate will start to dissolve in short order. However there are other benefits to be gained besides alliance against a powerful foe. If the distribution of power that is the de facto reality of this glued-together ramshackle realm is combined with the British drive toward capitalist industrialization that seems to exist in this timeline as well as our Victorian period, and the political machinery underlying the growth of capitalist production is less one-sidedly in the hands of the plutocrats in Britain and more a matter of gaining mutual assent from diverse frontier types, then a slightly restrained capitalism with a human face can easily serve as the glue that holds the realm together. Free trade--rather, loosely managed trade-- is much more easily handled among a bunch of subdomains that have a shared commitment both to imperial mutual defense and to mutual profit than among a bunch of separated nominally sovereign but dangerously weak entities.
One strength the Canadian realm will lack will be knowing what the alternatives are. If they could see sideways in time and compare the mess that would result from all these regions each trying to go it alone, they'd be that much more grateful, but they don't have that, so Dathi's task is to make the ongoing unity (such as it is!) of the sprawling and diverse possessions of BNA seem natural in its own context, without reference to the likely tragedies of it splitting up. I place a lot of hope in the ongoing wit and decency of the leadership keeping the terms of staying in reasonable and fair.
] as a way to get peace. Either route would probably avoid the degree of mistrust that results from just about everyone, including the Canadians, feeling betrayed to some degree.