Ruth Singer's monograph, Indigenous multilingualism at Warruwi, is a detailed linguistic ethnography of small-scale multilingualism in Warruwi, the Indigenous Mawng name for South Goulburn Island in Arnhem Land, Northern Australia. From the onset, Singer presents two main questions that guide her analysis of the linguistic and ethnographic data presented in the book: Why and how there are so many different Indigenous languages spoken at Warruwi? And how does a small language like Mawng continue to persist today in such a small community? On the surface, these questions might contradict each other. Yet Singer deftly illustrates the social dynamics present in Warruwi throughout the book, laying out the specific conditions that have enabled the persistence of small-scale multilingualism, as well as the continued use of Mawng, even amongst the youngest speakers at Warruwi.

The central focus of the book is Singer's description and analysis of ‘receptive multilingualism’ at Warruwi. As Singer notes, receptive multilingualism is not a singular phenomenon particular to northern Australia. However, what distinguishes receptive multilingualism at Warruwi is the fact that it is a widespread sociolinguistic phenomenon, raising interesting questions about the role of receptivity in shaping multilingual practices and repertoires, as well as the social significance of receptive multilingualism in the community. Singer presents receptive multilingualism as a form of interactive non-accommodation. Yet this non-accommodation should not be viewed as a form of social disharmony. Instead, such non-accommodative forms of receptive multilingualism reinforce a broader social ethos of being different together.

This recognition of differences as non-prohibitive of social cohesion and harmony is central to understanding how multilingual practices are balanced with an understanding of Warruwi being a Mawng-speaking place. Singer effectively illustrates this balance through the incorporation and analysis of language portraits that allow speakers at Warruwi to represent their bodies as the nexus of different languages, and the different proficiencies and knowledges associated with each linguistic medium. In these representations, Mawng is represented as the language of the land, situating the language as intimately linked with the place. Yet Mawng is not hierarchized or prioritized over other languages, highlighting the equality amongst linguistic codes that are a hallmark of small-scale multilingual communities. Furthermore, this equality is also indicative of earlier histories of contact between different clans of Mawng speakers, speakers of other Indigenous languages from Western and Eastern Arnhem land, and earlier moments of contact with Indonesian sailors that predated contact with White, European missionaries.

In short, this book makes significant contributions to recent re-orientations towards code-switching and multilingualism in the field. The details presented are notable in relation to other multilingual contexts in Australia, and other well-known cases of small-scale multilingualism like the Uaupes River in Northwest Brazil and the Casamance region in West Africa. This book offers insights into the ways that linguistic diversity is maintained in small communities, providing different perspectives in relation to theoretical discussions on language endangerment and revitalization.