In the current neoliberal era, work is increasingly connected to transnational relations that imply people crossing linguistic and national borders. Based on a multi-sited ethnography, this article explores a transnational social movement called Emmaus where voluntary work, geographical mobility, and language learning intersect. I analyse the role of language in narratives of (wanna-be) mobile volunteers in the Emmaus network. Volunteers need to learn and use linguae francae (English and Spanish) for voluntary work, which they justify with inter-cultural and solidarity tropes. Besides, they must navigate nation-state immigration laws and linguistic differences contrasting with their construction of Emmaus as a “safe zone” for transnational mobility and communication.