title: Adaptive Communication: Languages with More Non-Native Speakers Tend to Have Fewer Word Forms.
abstract: Explaining the diversity of languages across the world is one of the central aims of typological, historical, and evolutionary linguistics. We consider the effect of language contact-the number of non-native speakers a language has-on the way languages change and evolve. By analysing hundreds of languages within and across language families, regions, and text types, we show that languages with greater levels of contact typically employ fewer word forms to encode the same information content (a property we refer to as lexical diversity). Based on three types of statistical analyses, we demonstrate that this variance can in part be explained by the impact of non-native speakers on information encoding strategies. Finally, we argue that languages are information encoding systems shaped by the varying needs of their speakers. Language evolution and change should be modeled as the co-evolution of multiple intertwined adaptive systems: On one hand, the structure of human societies and human learning capabilities, and on the other, the structure of language.
authors.affiliation: Department of Theoretical and Applied Linguistics, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Christian
authors.initials: C
authors.lastname: Bentz
authors.affiliation: Reading Evolutionary Biology Group, School of Biological Sciences, University of Reading, Reading, United Kingdom.
authors.forename: Annemarie
authors.initials: A
authors.lastname: Verkerk
authors.affiliation: Computer Laboratory, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Douwe
authors.initials: D
authors.lastname: Kiela
authors.affiliation: Computer Laboratory, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Felix
authors.initials: F
authors.lastname: Hill
authors.affiliation: Department of Theoretical and Applied Linguistics, University of Cambridge, Cambridge, United Kingdom; Computer Laboratory, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Paula
authors.initials: P
authors.lastname: Buttery
mesh_terms: D003142:Communication; D006801:Humans; D007802:Language; D016018:Least-Squares Analysis; D016014:Linear Models; D008962:Models, Theoretical