Some bilingual societies exhibit a distribution of language skills that cannot be explained by economic theories that portray languages as pure communication devices. Such distribution of skills are typically the result of public policies that promote bilingualism among members of both speech communities (reciprocal bilingualism). In this paper I argue that these policies are likely to increase social welfare by diminishing economic and social segmentation between the two communities. However, these gains tend to be unequally distributed over the two communities. As a result, in a large range of circumstances these policies might not draw su ¢ cient support. The model is built upon the communicative value of languages, but also emphasizes the role of linguistic preferences in the behavior of bilingual individuals.