Where I live, there's also a local language (Frisian) spoken beside the 'bigger' language (Dutch). And here too, lots of people speak English. Or if not, you might get lucky with German.
I think there were almost no advantages to this dialect killing.
Small minority dialects are at a danger of dying out, not crowding out the bigger languages. This is how all of europe worked for hundreds of years. My Grandfather grew up speaking yiddish (german dialect) in school, czech in town & Hungarian at school. These are completely unrelated and individually difficult languages. He later went to college in German & Latin, later on English. He spoke 10 languages in total, most fluently. I knew him in a language that he learned in his 40s. This was normal in his day. They weren't afraid of languages then.
Anyway... if your "home" language is a tiny, local one. There is no danger that you will be monolingual in a commercially useless language. You will speak a big language too. Speaking 2 makes the 3rd one easier to learn.
^more on the dialect end of the spectrum than most people realize.
And it was purely the result of broadcast radio.
This article and map were pretty interesting:
http://www.slate.com/articles/arts/culturebox/2014/05/langua...
Where the government intervenes in the opposite direction, the transition can be much more rapid. Visiting Strasbourg (in Alsace, France), people's surnames, street and place names, and the local cuisine are all German, but nobody speaks a word of it. It was amazing (and slightly depressing) to see how in 2-3 generations a city could forget the language it spoke for nigh-on 1,500 years.
The way things are going, I wouldn't be surprised if Dutch were considered a dying language 50 years from now.
So it wasn't German very long, only 50 years.
As for Montreal, it will be interesting to see how the city evolves. I notice more English in my neighbourhood than when I moved in (8 years ago). But, there is also more French in the old anglo neighbourhoods of the west.
One factor is that a lot of "allophones" are perfectly fluent in both English and French. When you add in the francophone tendency to switch to English when dealing with anyone who shows even a whiff of not being a native francophone, a lot of francophone majority neighbourhoods may see English conversation.
(I'm perfectly fluent and speak French in public. But for the life of me I can't francophone friends to speak French. I think they all want to practice their English. Also, the Quebecois that care about Anglicization probably don't move to urban montreal)
Maybe they don't speak it normally, but I'm pretty sure a lot of people there can speak German. You can literally take a city bus (or walk) over the border into a German town Kiel. And everyone speaks German there. There are people who work in Strasbourg and live in Kiel, or vice versa.
The Alsatian dialect was always more of a rural thing. Both French and the Nazis suppressed it so unfortunately it's pretty rare these days. Still, according to Wikipedia, 43% of adults in Alsace could speak it in 1999. [1]
I used Welsh, Irish, Catalan and French-in-Quebec as examples because they're all languages that declined (to varying degrees) over several centuries under (varying degrees of) government suppression, experienced a partial rebound in interest and popularity in the 20th century after government policy was changed to encourage their use, but ultimately returned to the same trend of declining usage, something like
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0|suppressed encouragedAlso, because of concerns of linguistic extinction, similar to the ones mentioned for Icelandic in the article, you see somewhat of a counter-movement as well. This caused e.g. a special status of the language by law (see e.g. [1]), and also:
* it's a mandatory school subject
* you are entitled to using it in government interactions, e.g. in court
* a small part of the public television is in Frisian, and there's also a regional tv/radio channel using it exclusively
* place name signs are often at least bilingual, and sometimes Frisian-only.
[1]: https://en.wikipedia.org/wiki/European_Charter_for_Regional_...
I'd say even that can't accomplish much by itself, which is why the other things you listed are so important. A lot of Mexican-American kids in my hometown spoke exclusively Spanish at home, and now as adults if you ask them if they can speak Spanish most of them say "not really." They're embarrassed if they have to speak Spanish with someone from Mexico who has an adult vocabulary and a sophisticated grasp of the language. When your education, media, and social life is entirely in English, you end up so much more capable in English that that's all you want to speak. Even with their friends who also spoke Spanish at home, if the context of the conversation was their English-language schoolwork or an American band or an American TV show, it was more natural to talk about it in English; if there was somebody present they didn't know, it was safe to assume they spoke English; et cetera.
The tipping point is IMO what language people start conversations with. That shifts language skills and feeds off it's self.