Previous work has revealed general characteristics of language change at both the level of linguistic communities as well as individual speakers. What are the properties of language users such that we can account for these characteristics? To address this question, we built a computational model of a social network of language users. By holding the network structure constant and varying properties of the language users, we found that language change reflects both the structure of social networks and properties of language users. In particular, our results suggest that although language users must be capable of probabilistically accessing multiple grammars, they must prefer to access a single grammar categorically.