For any form of communication to make it beyond the category of talking to oneself, at least two individuals must share a common lexicon. Before languages can evolve into more complex forms, there must first be a pragmatic sense in which one individual can communicate a basic idea to another. How might shared lexicons have originated? Standard explorations of language often look in well-connected social groups such as chimpanzees, frequently numbering in the tens of individuals. But we might ask if language perhaps didn’t begin in a more humble arrangement, involving social groups of just two or a few individuals, such as that found in the orangutan? Agent-based models combined with network science offer a way to study this problem. By treating nodes as agents with strict rule-based behavior and edges as opportunities for interaction, agent-based models provide frameworks for studying how behavior and connectivity interact to create emergent phenomenon, such as the evolution of cooperation and cultural change. Here we will explore an agent-based model of the naming game to address how structure influences the emergence of shared lexicons.

Words, like biological species, are born and then, someday, they die. The half-life of a word is roughly 2,000 years, meaning that in that interval about half of all words are replaced with an unrelated (noncognate) word. Where do the new words come from? There are numerous dimensions along which new words could vary from old words, so it may not be easy to see how to enter this problem. However, extending our small worlds metaphor and the observation of clusters in language, we tell a simple story that mirrors biological theories about the origin of species. Language has urban centers with well-populated and well-connected meanings (like *food* and *red*). It also has rural fringes, where words live more isolated lives as hermits with limited connections to other words (like *twang* and *ohm*). Are new words more likely to be born in urban centers or in the rural fringes?