The mathematical model for language competition developed by Abrams and Strogatz allows the evolution of the numbers of monolingual speakers of two competing languages to be estimated. In this paper, we extend the model to examine the role of bilingualism and social structure, neither of which are addressed in the previous model. We consider the impact of two strategies for language maintenance: (1) adjusting the status of the endangered language; and (2) adjusting the availability of monolingual and bilingual educational resources. The model allows us to predict for which scenarios of intervention language maintenance is more likely to be achieved. Qualitative analysis of the model indicates a set of intervention strategies by which the likelihood of successful maintenance is expected to increase.