Digital communication remains largely unexplored in sociolinguistic research on diaspora and language. In this paper, ethnographically collected data from Norway-based families of Senegalese heritage are explored to identify how family members use digital media to engage with diaspora concerns and projects, and how this engagement shapes their multilingual practices online. We re-contextualize the concept of polycentricity (Blommaert et al.) from the physical setting of a neighbourhood or region to complex ecologies of digital media, and identify four 'centres', that is, distinct orientations for participants' digital language and literacy practices, in which linguistic choices are associated with diaspora discourses, genres, and imagery. Each centre constrains the deployment of linguistic and semiotic resources in ways that are related both to historically rooted sociolinguistic hierarchies and affordances of digital media. The findings support a key claim in language and diaspora research, that is, the fine-grained patterning of linguistic resources in diaspora communities. They also underscore the need to extend the empirical scope of a sociolinguistics of diaspora from co-present to mediated interaction, and to explore the interplay between the two.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.