IN 1980, Daniel Everett, an American missionary and linguist, set off into the heart of the Amazon to track down some of the norld's most elusive words: the language of the Pirahã, a small tribe of Amazonian Indians living on the banks of the Maici River in Brazil.

For the next 20 years Everett, the son of a California cowboy, tried to hack his way through this impenetrable language, coming across verbs that grew into the most contorted shapes, sentences without subordinate clauses and forests of nouns that seemed to change without reason or pattern.

Pirahã, now spoken by fewer than 400 people, is not related to any other known living language, the people who speak it are monolingual, no outsider had ever mastered it before. The language has no simple colour words, no comparatives, no abstract concepts, no stories of the past, nor visions of the future. The Pirahã have no history, no fiction, no creation myth and no folklore. They have no concept of numbers, and no sense of right or left.

Intending to shed the light of Christianity on the tribe by translating the Bible into Pirahã, Everett found himself lost in an alien tongue.

The language has three vowels and eight consonants for men, and the same number of vowels but only seven consonants for women. There is a supply of nouns, but each verb has up to 16 suffixes, which may be present or absent: thus, 2 to the power of 16, making 65,536 possible forms for each and any Pirahã verb. To complicate matters further, there is hum speech, musical speech and whistle speech. Struggling through the linguistic undergrowth was only one challenge, alongside anacondas, tarantulas and river pirates. Everett's wife and daughter caught malaria and almost died. He watched in horror as the Pirahã killed an orphaned baby, on the ground that the child would soon die anyway.

As his command of Pirahã grew, he explored deeper into this linguistic terra incognita. Here was a people so in tune with their surroundings that they had no north or south, no left or right, but merely “upriver” and “downriver”, a direction hard-wired into their speech, like a GPS. They have no need of numbers, and thus no quantifiers - no words meaning all, each or every. For eight months, Everett tried to teach them to count, entirely without success.

Pirahã, he concluded, was predicated on the “immediacy of experience”. The language consisted of questions, declarations, or commands, all directly related to the tribe's visible world. “The Pirahã only make statements that are anchored in the moment,” he writes. “Declarative Pirahã utterances contain only assertions related directly to the moment of speech, either experienced by the speaker or witnessed by someone alive during the lifetime of the speaker.”

This is a language of the here and now. The Pirahã and their language live from day to day. “Pirahãs don't store food, they don't plan more than one day at a time, they don't talk about the distant future or the distant past - they seem to focus on now, on their immediate experience.” Everett's most astonishing find was that the Pirahã lack the grammatical principle of recursion, thoughts collected together in sentences with more than one clause. Noam Chomsky held that recursion is common to all language, and that the ability to use grammar is what sets humanity apart from all other terrestrial life forms. But recursion requires abstraction and generalisation that contravene Everett's “immediacy of experience principle”. “It is not simply that Pirahã accidentally lacks recursion. It doesn't want it; it doesn't allow it because of a cultural principle.”

Like most explorers, and many linguists, Everett is plainly an obsessive. After years of living in the Amazonian jungle, he found himself drawn to the Pirahã way of seeing the world: his marriage and his faith collapsed. “The Pirahãs simply make the immediate their focus of concentration, and thereby, at a single stroke, they eliminate huge sources of worry, fear and despair that plague so many of us in Western societies.”

This is an astonishing book: a work of exploration, into the most distant place and language, but also a revelation of the way language is shaped by thought and circumstance. Everett came to the jungle intending to teach and convert though language, but was con-verted to a new way of thinking.

“Do not sleep there are snakes” is a Pirahã saying. Members of the tribe sleep little, and tend to chat through the night, but the expression is more than just a warning. Everett translates it as “Life is hard, and there is plenty of danger. And it might make us lose some sleep from time to time. But enjoy it. Life goes on.”

The Pirahã live, and speak, for now, and in their strange tongue they have retained something we have lost.

Don't Sleep there are Snakes: Life and Language in the Amazonian Jungle by Daniel Everett is published by Profile next month.

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