This study takes an experimental approach to "lingua receptiva" (LaRa), a communication mode in which interlocutors each use their own--different--native language. In contrast to previous work on LaRa, this study investigates the phenomenon in genetically unrelated languages. Native speakers of Estonian and Russian were engaged in a "map task", which requires verbal interaction in the service of problem solving, i.e. finding locations on a map. It is assumed that successful communication requires "alignment", a state that is established once the interlocutors have reached a shared understanding of relevant aspects of reality. The goal of this exploratory study is twofold: (1) to test whether the current methodology can help detect alignment in LaRa and (2) to determine what factors -- linguistic, communicative as well as meta-communicative -- contribute to success (i.e. completing the task). Specific attention was given to the effect of participants' proficiency in the language used by their interlocutor. The results suggest that alignment in LaRa must be achieved by active monitoring and the application of meta-communicative devices (MCDs), the explicit negotiations aimed at establishing mutual understanding. Efficient dyads reach and maintain alignment by "minding" their languages via the application of these MCDs. Furthermore, it is found that L2 proficiency does not impact strongly on communicative success; dyads with various L2 proficiencies were able to complete the task in lingua receptiva successfully.