Linguistic norms emerge in human communities because people imitate each other. A shared linguistic system allows people to enjoy the benefits of shared knowledge and coordinated planning. Once norms are in place, why would they ever change? This question, echoing broad questions in the theory of social dynamics, has particular force in relation to language. By definition, an innovator is in the minority when the innovation first occurs. In some areas of social dynamics, important minorities can exercise disproportionate influence on the majority through their power, fame, or use of broadcast media. But most linguistic changes are grassroots developments that originate wit ordinary people. In this talk, I will present a novel model of communicative behavior in communities (developed with Robert Daland and Forrest Stonedahl), and identify a mechanism for arbitrary innovations by ordinary people to have a good chance of being widely adopted.

To imitate each other, people must form a mental representation of what other people do. Each time they speak, they must also decide which form to produce themselves. I introduce a new decision function that makes it possible to smoothly explore the space between two types of behavior: frequency-tracking, whereby people reproduce the relative frequencies in their experience, and regularization, whereby people produce frequent forms disproportionately often. The interaction amongst the degree of regularization, the distribution of biases in a social network, and the network position of the innovator are explored using Monte Carlo simulations. Crucially, with moderate regularization of experienced input, average people (not well-connected people) are the most likely source of successful innovations. These results shed light on a major outstanding puzzle in the theory of language change. They have broad implications for research on statistical learning in language acquisition.