Of the roughly seven thousand languages spoken in the world today, experts predict that nearly half may disappear before the end of this century. On average, it is said, a language falls silent somewhere in the world every few weeks, as its last fluent speaker dies. To many people, this may seem unimportant, or even a natural part of progress. Yet the loss of a language is a loss for all of humanity, and understanding why reveals something profound about the value of human diversity.

Languages die for many reasons. Sometimes speakers are actively discouraged or forbidden from using their mother tongue. More often, the process is gradual and voluntary: a small community’s language comes to be seen as less useful than a dominant national or global language, so parents choose to raise their children speaking the language that offers better opportunities. Within a generation or two, the older language survives only among the elderly, and then not at all.

Why does this matter? Each language is far more than a collection of words. It is a unique way of understanding and describing the world, shaped by the history, environment and culture of the people who speak it. Some languages contain detailed knowledge of local plants, animals and weather that exists nowhere else. Others express ideas and relationships that cannot be translated neatly into English or any other tongue. When a language disappears, this accumulated wisdom, built up over countless generations, vanishes with it.

Fortunately, the situation is not hopeless. Around the world, communities and linguists are working together to record endangered languages and, in some inspiring cases, to bring them back into everyday use. Technology, which has often accelerated language loss, is now being used to teach and preserve threatened tongues. Reviving a language is difficult and slow, and not every language can be saved. But each success represents the survival of an irreplaceable way of seeing the world – and a richer, more varied future for us all.