This paper reviews the current state of knowledge about the links -metaphorical and real -between cultural and biological diversity. By way of approach, it focuses on language and music cultures, two areas of intangible cultural heritage whose diversity has come under threat in recent decades. The paper suggests some ways in which recent advances in the fields of ecolinguistics, biolinguistic diversity, and music sustainability further our knowledge of the links between cultural diversity and biodiversity. Metaphorical parallels between biodiversity and cultural diversity (such as the interconnectedness of the various forms of intangible cultural heritage, as in a biological ecosystem) can, to some extent, inform the development of models for supporting intangible cultural heritage such as language and music. Moreover, the very real interconnections between these two kinds of 'diversities' hold implications for cultural heritage management, since efforts to safeguard cultural diversity will be impacted by the successes and failures of efforts to protect biodiversity, and vice versa. For this reason, the issues explored in this review hold implications for policymakers, governments, non-governmental organisations, culture-bearers themselves, and other stakeholders in the viability and diversity of cultural heritage.