This article examines how power and solidarity in family relations are negotiated along linguistic lines, and in particular, the role of a third language in this negotiation process. It takes as its case study a transnational family in Ireland who practise a strongly pro-Polish FLP and where the parents are seen as authorities in Polish and their daughters are seen as authorities in English, the dominant societal language. The paper takes a microinteractional approach to analysing excerpts where family members engage in language-learning activities using Irish, the national autochthonous minority language. The paper demonstrates how in many ways, Irish operates as a neutral, third space for family members to negotiate power/solidarity alignments, and thus contributes to the family's maintenance of the power/solidarity equilibrium. The paper also demonstrates the polysemy inherent in how these negotiations play out at an interactional level, especially vis-à-vis the family's pro-Polish FLP, as well as the polysemy of Irish-as-a-language within the scope of the family's interactions as a whole.