Books about endangered languages tend to be laments, full of shocking statistics and portraits of impossibly frail, ancient last speakers in faraway places. Ross Perlin’s exuberant, radical book blasts that away, exploring, instead, New York, now ‘the most linguistically diverse city in the history of the world’, home to more than 700 languages (of approximately 7,000 on the planet), and a ‘last improbable refuge’ for many speakers of ‘embattled and endangered’ tongues.