I don't know that language is necessarily a barrier to success, as there are large communities that speak a language other than English or French, and one could operate within that community.  In fact there are some areas where malls and strip malls have business signage only in non-official languages.  So I don't think not knowing one of the official languages is necessarily an economic hurdle, but it would certainly prevent newcomers from integrating on the whole.   Shouldn't a goal of immigrants be to integrate?