This chapter describes a plurilingual approach to literacies which embraces the expression of plurilingual identities by adult migrants who have crossed geographic, linguistic and cultural borders. It focuses on a creative writing workshop that created and facilitated with plurilingual learners in French as a Second Language (FSL) class at a French university, as part of teaching practice as a FSL teacher. Then, the chapter provides samples of learners' written pieces and discourses that reveal clear evidence of heterogeneity and dialogism in their plurilingual literacy practice. Heterogeneity is understood as the co-existence of diverse and mixed forms of a language in texts, and dialogism as the manifestation. Additionally, it is necessary to research further how the plurilingual repertoires of adult migrants can be valued beyond the writing workshop and in the mainstream. Finally, it draws links to the expression of plurilingual identities and implications for adult language education.