All Together Now: Complementary Community Roles in Language Creation

The emergence of new languages offers a rare opportunity to observe how linguistic structure arises and evolves. We examine language creation through a developmental lens, focusing on how individuals at different life stages engage in complementary processes of invention, stabilization, and transmission. Drawing primarily on a new sign language [Lengua de Señas Nicaragüense (LSN)] that has emerged over the past five decades, we highlight how child learners drive innovation by reanalyzing patterns in their environment, while adolescents and adults promote convergence, model established forms, and create the social conditions for transmission. We illustrate these dynamics closely in the emergence of grammatical devices that encode argument structure. Variation across the community today shows how a language encodes its history, synchronically reflecting cumulative contributions across generations. Viewing language creation as a developmental process thus underscores the joint influence of biological learning biases, social interaction, and cultural evolution in shaping human communication.