Mediation strategies are deployed when people use translation, interpreting, lingua francas, intercomprehension, language learning, or any combination of these to communicate in situations where there is more than one language in play. Such choices can be seen as enacting trade-offs between the goals of mobility (across geolinguistic borders) and inclusion (primarily into labor markets and government services). Mediation strategies are nevertheless selected in accordance with complex sets of criteria by which they are evaluated and compared in each particular situation. Case studies suggest that, if seen as performative language policy, the strategies tend to give more priority to social inclusion than to language diversity. They might thus constitute a challenge to some approaches to official language policy.