1 Group polarization on social media: Comparing the dynamics of interaction networks and language-based opinion distributions Kevin Durrheim Maria Schuld University of Johannesburg Corresponding author: Kevin Durrheim Email: kevind@uj.ac.za Keywords: Polarization; Social media; Speaker Landscapes; Opinions; Social Networks Running head: GROUP POLARIZATION ON SOCIAL MEDIA Acknowledgement: This research was supported by funding from the National Research Foundation of South Africa (Grant UID: 137755) and by The South African Centre for Digital Language Resources (SADiLaR) (Grant OR-AAALV). We are grateful to Ignacio Ojea Quintana, Ritsaart Reimann, Marc Cheong, Mark Alfano, and Colin Klein, for making their data available to us.