A new paper in PLoS ONE argues that human languages may adapt like biological organisms. By doing a large-scale analysis of over 2,000 of the worldâ€™s languages the authors find striking relationships between the demographic properties of a languageâ€”such as its population and global spreadâ€”and the grammatical complexity of those languages. Languages with the most speakers (like English) were found to have far simpler grammars than languages spoken by few people and in circumscribed regions. This reminds me to bottlenecks in population history (and founder effects for certain DNA variants) while the authors describe this phenomenon as â€œLinguistic Nicheâ€. A Hardy Weinberg Equilibrium of declension types?