This NWO Open Competition L project is a collaboration between UU GEO (Derek Karssenberg - FG, Sietze Norder – Copernicus, and Judith Verstegen – SGPL), University of Groningen (Nick Emlen), and Leiden Centre for Linguistics (group of Rik van Gijn). A language family arises as a result of the diversification over time of the speech variants of groups that once spoke one and the same language but followed differential historical trajectories. These socio-historical processes took place all over the world, but they have led to radically different patterns of linguistic diversity from one area to another. This project aims to understand the interplay between the biophysical environment and the social processes of diversification to explain the patterns of linguistic diversity we see today. It will employ two distinct approaches: 1) areal-typological approach, combined with regionally informed qualitative contextualization, performed by a PhD student in Leiden, and 2) a spatial agent-based modelling approach, simulating how languages (agents) change, merge, and split over time, performed by a PhD student in Utrecht. The PhD students will work on the same case studies in South America.