I like the "societal culture" concept. Two great societal cultures in Canada gave birth to two official languages. The point is simply that francophones outside Quebec share the same societal culture as Quebec and, reciprocally, that anglophones in Quebec share the same societal culture as anglophones in Canada.
It's here that we can make use of a concept that I probably don't have enough time to explain, and that is the concept of "cultural autonomy". New Brunswick is probably the best example of it with its duality concept, in which institutions belong to the groups. The more we can apply this concept, the better it will be for the minority groups.