The aim of this study is to set out to explore how children living in Polish-English transnational families in the UK develop "symbolic competence" and "symbolic power" in home settings. By focusing on the children's use of metaphor in family discourse when talking about the Moon, from a cognitive discursive perspective, this study explores the children's creative use of language in achieving their social goals. It moves beyond seeing language, cognition and culture as bounded systems but rather powerful meaning-making resources that are part of the children's complex discourse-worlds. The findings show how transnational families provide children rich opportunities to develop intercultural or 'transcultural' competence.