Drawing on discursive data collected during an 18-month reflexive critical ethnography of the transition to postsecondary education, this paper explores how graduates of a French first-language secondary school in Ontario, Canada, struggle to affirm their linguistic identity in their new academic and social communities. Despite not crossing geopolitical boundaries, they have crossed borders as they integrate new, more culturally diverse but narrow language ideology spaces quite different from their high school linguistic community and their family environments. After a lifetime of seamless crossing over and back between two linguistic realities (Francophone and Anglophone), as invisible and inaudible minorities, these students have no experience of having their linguistic identity contested by peers or figures of authority, whether Francophone or Anglophone. They are unprepared for the social exclusion that begins prior to graduation when their linguistic loyalty is questioned in their home communities based on the language of instruction of their chosen postsecondary institution. They are further unprepared for the social exclusion that ensues in postsecondary milieus when confronted by homogeneous ideologically narrow conceptions of linguistic identity.