Supplementary material for "Sociogeographic correlates of typological variation in northwestern Bantu gender systems" by Annemarie Verkerk and Francesca Di Garbo, published in LDC, 2022

These are the supplementary materials for an article published in Language Dynamics and Change (LDC) entitled "Sociogeographic correlates of typological variation in northwestern Bantu gender systems", by Annemarie Verkerk and Francesca Di Garbo, with DOI 10.1163/22105832-bja10017. This paper investigates the sociolinguistic factors that impact the typology and evolution of grammatical gender systems in northwestern Bantu, the most diverse area of the Bantu-speaking world. We base our analyses on a typological classification of 179 northwestern Bantu languages, focusing on various instances of semantic agreement and their role in the erosion of gender marking. In addition, we conduct in-depth analyses of the sociolinguistics and population history of the 17 languages of the sample with the most eroded gender systems. The sociohistorical factors identified to explain these highly eroded systems are then translated into a set of explanatory variables, which we use to conduct extensive quantitative analyses on the 179 language sample. These variables are population size, longitude, latitude, relationship with the Central African rainforest, and border with Ubangi/Central Sudanic languages. All these measures are relevant, with population size and bordering with Ubangi/Central Sudanic being the most robust factors in accounting for the distribution of gender restructuring. We conclude that fine-tuned variable design tailored to language and area-specific ecologies is crucial to the advancement of quantitative sociolinguistic typology. These supplementary materials consist of the relevant code and data used for this study, with accompanying figures and details on the analyses.