The English colonization of Ireland suppressed the Irish language, but the advent of the Irish republic showed you can virtually extinguish a language, and not kill nationalism. British Lord Durham wanted to assimilate Quebecers to the English language majority.
The Act of Union of 1840 failed to achieve that imperial objective, and the Irish example suggests that even if the French language had been substantially weakened, Quebec nationalism would not have disappeared.
The history of de-colonization shows how much trouble multi-linguistic states have creating a sense of identity strong enough to engender national feelings. The primary attachment remains the linguistic community.