May God grant you goodness and beauty! The Ubykh language ends here.” In Ecuador, Martha, a social worker, is encouraging midwives and expectant parents to speak the Kichwa language to babies in the womb in an attempt to ensure that the language – threatened by the dominance of Spanish – can be safeguarded for the next generation. In How to Kill a Language, Sophia Smith Galer, who grew up in London hearing her nonna’s “dialët”, a rare variety of Italian spoken high in the Apennines, goes in search of endangered languages and their speakers, and urges the defence of a linguistic diversity which is being lost.

We are living through an era of linguistic extinction. There are about 7,000 languages in use around the world today; by the next century, we’ll be lucky if that number is 4,000. Linguicide means the death of a language.

For Smith Galer, that could be by active effort, as in the Turkish government’s long-running repression of Kurdish, or by simple neglect. Many dialects of the Italian peninsula have been killed by kindness: money is available to support them, but they are presented more as museum pieces for historical appreciation than serious candidates for revival and regular use. Language extinction is often compared with the destruction of the Earth’s biodiversity.

Climate change and language death are closely linked. Smith Galer travels to northern Ghana to meet speakers of Dagbani, a tonal language under threat from climate-based migration, and these climate migrants’ adoption of new languages needed to make a life in their latest environment. Displacement can disrupt the relationship between language and land, and the decline of indigenous languages like Karuk in northern California also threatens the rich vocabulary that helps to describe the plants and animals of the region.

What can be done to save languages from dying? Even as the situation is critical, Smith Galer sees reason for hope in a variety of language revitalisation approaches. Take New Zealand’s “language nests” that since the Eighties have been enlisting fluent speakers of te reo Māori to speak the language to children.

Tourism can threaten endangered languages but responsible approaches (and the money that comes with them) offer some hope to speakers of Shehret in the mountains of southern Oman. There are punchier state-supported initiatives, like Ukraine’s 2019 language law mandating 50 per cent or more of a publisher’s output be in Ukrainian. Hebrew is probably the greatest success story in of language revitalisation, having successfully transitioned from an ancient tongue to a modern official language through the efforts of figures like Eliezer Ben-Yehuda, a Jewish linguist born in Russia in 1858, who insisted on his son being raised in a monolingual Hebrew environment – the first child to experience that in nearly two millennia.

But Hebrew’s triumph came at the expense of other Jewish vernaculars like Yiddish or Ladino, which Smith Galer tracks down to the last remaining speakers in Greece’s second most populous city, Thessaloniki. A century ago more people spoke Ladino there than Greek. This is a necessary book, with a message that English speakers need to hear.

Smith Galer writes that “Native English speakers enjoy a cultural dominance so ubiquitous we hardly notice it. I hope this book has disturbed any sense that this is a good or inevitable fact.” In the UK, there have been recent success stories in the revitalisation of Welsh and Scottish Gaelic, though neither language can trust that their future existence is secure. Meaningful support for minority languages and the recognition of their speakers’ rights are essential if we are to hold off a mass language-extinction event in our near future.

Equally essential, at a time when politicians and polemicists take aim at linguistic diversity as a sign of societal fragmentation, is a more tolerant attitude to multilingualism in all of our societies, and a recognition of what we lose when we speak only one language. How to Kill a LanguageSophia Smith GalerWilliam Collins, 304pp, £22 Purchasing a book may earn the NS a commission from Bookshop.org, who support independent bookshops [Further reading: Franz Kafka’s ten apostles]