The World Until Yesterday: What Can We Learn From Traditional Societies?

by Jared Diamond

  It was initially expected that this advantage of bilinguals at tests involving rule changes or confusing information would apply only to tasks involving verbal cues. However, the advantage proves to be broader, and to apply also to non-verbal cues of space, color, and quantity (as in the two examples that I just described). But this hardly means that bilinguals are better than monolinguals at everything: the two groups tend to perform equally well at tasks without rule changes to be attended to, and without misleading cues to be ignored. Nevertheless, life is full of misleading information and changing rules. If bilinguals’ advantage over monolinguals in these trivial games also applies to the abundance of confusing or shifting real-life situations, that would mean a significant advantage for bilinguals.

  One interesting recent extension of these comparative tests is to infants. One might imagine that it would be meaningless or impossible to test “bilingual infants”: infants can’t speak at all, they can’t be described as bilingual or monolingual, and they can’t be asked to perform tests by sorting cards and pushing keys. In fact, infants develop the ability to discriminate speech that they hear long before they can speak themselves. One can test their powers of discrimination by watching whether they can learn to orient differently to two different sounds. It turns out that newborn infants, who have had no exposure to any of the world’s languages, can discriminate between many consonant and vowel distinctions used in one or another of the world’s languages, whether or not it happens to be their “native” language (which they haven’t heard except from inside the womb). Over the course of their first year of life, as they hear speech around them, they lose that initial ability of theirs to discriminate non-native distinctions that they aren’t hearing around them, and they sharpen their ability to discriminate native distinctions. For instance, the English language discriminates between the two liquid consonants l and r, while the Japanese language doesn’t; that’s why native Japanese people speaking English sound to native English-speakers as if they are mispronouncing “lots of luck” as “rots of ruck.” Conversely, the Japanese language discriminates between short and long vowels, while the English language doesn’t. However, newborn Japanese infants can discriminate between l and r, and newborn English infants can discriminate between short and long vowels, but each loses that ability over the first year of life because the distinction carries no meaning.

  Recent studies have concerned so-called crib bilinguals: i.e., infants whose mother and father differ from each other in native language, but whose mother and father have both decided to speak her or his own language to the infant already from day 1, so that the infant grows up hearing two languages rather than just one language. Do crib bilinguals already gain over monolinguals the advantage in executive function, enabling them to deal better with rule switches and confusing information, that is apparent after the child can actually speak? And how does one test executive function in a pre-verbal infant?

  A recent ingenious study by the scientists Ágnes Kovács and Jacques Mehler, carried out in the Italian city of Trieste, compared seven-month “monolingual” infants with infants “bilingual” in Italian plus either Slovenian, Spanish, English, Arabic, Danish, French, or Russian (i.e., hearing one language from their mother and the other language from their father). The infants were trained, conditioned, and rewarded for correct behavior by being shown a cute picture of a puppet popping up on the left side of a computer screen; the infants learned to look in the direction of the puppet and evidently enjoyed it. The test consisted of pronouncing to the infant a nonsense trisyllable with the structure AAB, ABA, or ABB (e.g., lo-lo-vu, lo-vu-lo, lo-vu-vu). For only one of the three structures (e.g., lo-lo-vu) did the puppet appear on the screen. Within 6 trials, on hearing lo-lo-vu both “monolingual” and “bilingual” infants learned to look towards the left side of the screen to anticipate the appearance of the cute puppet. Then the experimenter changed the rules and made the puppet appear on the right side (not on the left side) of the screen, in response not to the nonsense word lo-lo-vu but to lo-vu-lo. Within 6 trials, the “bilingual” infants had unlearned their previous lesson and had learned the new correct response, but the “monolingual” infants even after 10 trials were still looking at the now-wrong side of the screen on hearing the now-wrong nonsense word.

  Alzheimer’s disease

  One can extrapolate from these results, and speculate that bilingual people may have an advantage over monolingual people in negotiating our confusing world of changing rules, and not merely in the trivial tasks of discriminating lo-lo-vu from lo-vu-lo. However, you readers will probably require evidence of more tangible benefits before you make the commitment to babble consistently in two different languages to your infant children and grandchildren. Hence you will be much more interested to learn about reported advantages of bilingualism at the opposite end of the lifespan: old age, when the devastating tragedy of Alzheimer’s disease and other senile dementias lies in store for so many of us.

  Alzheimer’s disease is the commonest form of dementia of old age, affecting about 5% of people over the age of 75, and 17% of those over the age of 85. It begins with forgetfulness and a decline of short-term memory, and it proceeds irreversibly and incurably to death within about 5 to 10 years. The disease is associated with brain lesions, detectable by autopsy or (in life) by brain-imaging methods, including brain shrinkage and accumulation of specific proteins. All drug and vaccine treatments to date have failed. People with mentally and physically stimulating lives—more education, more complex jobs, stimulating social and leisure activities, and more physical exercise—suffer lower rates of dementia. However, the long latency period of up to 20 years between the beginning of protein build-up and the later appearance of Alzheimer’s symptoms raises questions of cause and effect about the interpretation of these findings concerning stimulating lives: does stimulation itself really decrease Alzheimer’s symptoms, or were those individuals instead able to lead stimulating lives precisely because they were not suffering from early stages of protein build-up, or because of genetic advantages that also protected them against Alzheimer’s disease? In the hope that stimulating lives might be a cause rather than a result of reduced disease processes, older people afraid of developing Alzheimer’s disease are sometimes urged to play bridge, play challenging online games, or solve Sudoku puzzles.

  Intriguing results of the last few years suggest a protective effect of life-long bilingualism against Alzheimer’s symptoms. Among 400 patients studied at clinics in Toronto, Canada, mostly in their 70s, and with a probable diagnosis of Alzheimer’s disease (or other dementias in a few cases), bilingual patients showed their first symptoms at an age 4 or 5 years older than did monolingual patients. Life expectancy in Canada is 79, hence a delay of 4–5 years for people in their 70s translates into a 47% decrease of probability that they will develop Alzheimer’s symptoms at all before they die. The bilingual and monolingual patients were matched in occupational status, but the bilingual patients had received on the average lower (not higher) levels of education. Because education is associated with lower incidence of Alzheimer’s symptoms, this means that differences in education could not explain the lower incidence of symptoms in the bilingual patients: their lower incidence was despite their having received less education. A further intriguing finding was that, for a given level of cognitive impairment, bilingual patients had more brain atrophy revealed by brain-imaging methods than did monolingual patients. Expressing this differently, bilingual patients suffer less cognitive impairment than do monolingual patients with the same degree of brain atrophy: bilingualism offers partial protection against the consequences of brain atrophy.

  The protection afforded by bilingualism does not raise the same uncertainties of interpretation about cause versus effect raised by the apparent protection offered by education and stimulating social activities. The latter might be results rather than causes of early stages of Alzheimer’s lesions; and genetic factors predisposing one to seek education
and social activities might also protect one against Alzheimer’s disease. But whether one becomes bilingual is determined in early childhood, decades before the earliest Alzheimer’s brain lesions develop, and regardless of one’s genes. Most bilingual people become bilingual not through any decision or genes of their own, but through the accident of growing up in a bilingual society, or of their parents emigrating from their native land to a land with a different language. Hence the reduced Alzheimer’s symptoms of bilinguals suggest that bilingualism itself protects against Alzheimer’s symptoms.

  How might this be? A short answer is the aphorism “Use it or lose it.” Exercising most body systems improves their function; failing to exercise them lets their function deteriorate. This is the reason why athletes and artists practise. It’s also the reason why Alzheimer’s patients are encouraged to play bridge or online games, or to solve Sudoku puzzles. But bilingualism is the most constant practice possible for the brain. Whereas even a bridge or Sudoku fanatic can play bridge or solve Sudoku puzzles for only a fraction of a day, bilingual people impose extra exercise on their brain every second of their waking hours. Consciously or unconsciously, their brain is constantly having to decide, “Shall I speak, think, or interpret sounds spoken to me according to the arbitrary rules of language A, or of language B?”

  Readers will share my personal interest in some unanswered but obvious further questions. If one extra language offers some protection, do two extra languages offer more protection? If so, does the protection increase in direct proportion to the number of languages, or else more steeply or less steeply? For instance, if bilingual people get four years of protection from their one extra language, does a New Guinean, an Aboriginal Australian, a Vaupés River Indian, or a Scandinavian shopkeeper speaking five languages (four beyond her first language) still get just 4 years of protection, or does she get 4 × 4 = 16 years of protection, or (if juggling four extra languages is much more than four times more taxing than juggling just one extra language) does she even get 50 years of protection? If you had the misfortune that your parents didn’t raise you as a crib bilingual, and that you didn’t learn a second language until you began high school at age 14, can you ever catch up to crib bilinguals in the benefits obtained? Both of these questions will be of theoretical interest to linguists, and of practical interest to parents wondering how best to raise their children. All of this suggests that bilingualism or multilingualism may bring big practical advantages to bilingual individuals, beyond the less practical advantages of a culturally enriched life, and regardless of whether language diversity is good or bad for the world as a whole.

  Vanishing languages

  The world’s 7,000 languages are enormously diverse in a wide range of respects. For instance, one day while I was surveying birds in jungle around Rotokas village in the mountains of the Pacific island of Bougainville, the villager guiding me and naming local birds for me in the Rotokas language suddenly exclaimed “Kópipi!” as he pointed out the most beautiful bird song that I had ever heard. It consisted of silver-clear whistled tones and trills, grouped in slowly rising phrases of two or three notes, each phrase different from the previous one, and producing an effect like one of Franz Schubert’s deceptively simple songs. The singer proved to be a species of long-legged short-winged warbler previously unknown to Western science.

  As I talked with my guide, I gradually realized that the music of Bougainville’s mountains included not only the kópipi’s song but also the sound of the Rotokas language. My guide named one bird for me after another: kópipi, kurupi, vokupi, kopikau, kororo, keravo, kurue, vikuroi…. The only consonant sounds from those names are k, p, r, and v. Later, I learned that the Rotokas language has only 6 consonant sounds, the fewest of any known language in the world. English, by comparison, has 24, while the now-extinct Ubykh language of Turkey had about 80. Somehow, the people of Rotokas, living in a tropical rainforest on the highest mountain of the Southwest Pacific Ocean east of New Guinea, have managed to build a rich vocabulary and communicate clearly while relying on fewer basic sounds than any other people in the world.

  But the music of their language is now disappearing from Bougainville’s mountains, and from the world. The Rotokas language is just 1 of 18 languages spoken on an island roughly three-quarters the size of the American state of Connecticut. At last count it was spoken by only 4,320 people, and that number is declining. With its vanishing, a 30,000-year experiment in human communication and cultural development will come to an end. That vanishing exemplifies the impending tragedy of the loss not just of the Rotokas language, but of most of the world’s other languages. Only now are linguists starting seriously to estimate the world rate of language loss, and to debate what to do about it. If the present rate of language disappearance continues, then by the year 2100 most of the world’s current languages will either already be extinct, or else will be moribund languages spoken only by old people and no longer being transmitted from parents to children.

  Of course, language extinction isn’t a new phenomenon that began only 70 years ago. We know from ancient written records, and we infer from distributions of languages and peoples, that languages have been going extinct for thousands of years. From Roman authors and from scraps of writing on ancient monuments and coins in the territory of the former Roman Empire, we know that Latin replaced Celtic languages formerly spoken in France and Spain, and replaced Etruscan, Umbrian, Oscan, Faliscan, and other languages within Italy itself. Preserved ancient texts in Sumerian, Hurrian, and Hittite attest to now-vanished languages spoken several thousand years ago in the Fertile Crescent. The spread of the Indo-European language family into western Europe, beginning within the last 9,000 years, eliminated all the original languages of Europe except for the Basque language of the Pyrenees. We infer that African Pygmies, Philippine and Indonesian hunter-gatherers, and ancient Japanese people spoke now-vanished languages replaced by Bantu languages, Austronesian languages, and the modern Japanese language respectively. Far more languages must have vanished without a trace.

  Despite all that evidence for past extinctions of languages, modern language extinctions are different because of their greatly increased rate. Extinctions of the last 10,000 years left us with 7,000 languages today, but extinctions of the next century or so will leave us with only a few hundred. That record-high rate of language extinction is due to the homogenizing influences of the spreads of globalization and of state government over the whole world.

  As an illustration of the fates of most languages, consider Alaska’s 20 native Inuit and Indian languages. The Eyak language, formerly spoken by a few hundred Indians on Alaska’s south coast, had declined by 1982 to two native speakers, Marie Smith Jones and her sister Sophie Borodkin (Plate 47). Their children speak only English. With Sophie’s death in 1992 at the age of 80, and Marie’s death in 2008 at the age of 93, the language world of the Eyak people reached its final silence. Seventeen other native Alaskan languages are moribund, in the sense that not a single child is learning them. Although they are still spoken by older people, they too will meet the fate of Eyak when the last of those speakers dies, and almost all of them have fewer than a thousand speakers each. That leaves only two native Alaskan languages still being learned by children and thus not yet doomed: Siberian Yupik, with 1,000 speakers, and Central Yupik, with a grand total of 10,000 speakers.

  In monographs summarizing the current status of languages, one encounters the same types of phrases monotonously repeated. “Ubykh [that Turkish language with 80 consonants]…the last fully competent speaker, Tevfik Esen, of Haci Osman, died in Istanbul 10/92. A century ago there were 50,000 speakers in the Caucasus valleys east of the Black Sea.” “Cupeño [an Indian language of southern California]…nine speakers out of a total population of 150…all over 50 years old…nearly extinct.” “Yamana [an Indian language formerly spoken in southern Chile and Argentina]…three women speakers [in Chile], who are married to Spanish men and raised their children as Spanish spe
akers…extinct in Argentina.”

  The degree of language endangerment varies around the world. The continent in most desperate straits linguistically is Aboriginal Australia, where originally about 250 languages were spoken, all with under 5,000 speakers. Today, half of those Australian languages are already extinct; most of the survivors have under 100 speakers; fewer than 20 are still being passed on to children; and at most a few are likely still to be spoken by the end of the 21st century. Nearly as desperate is the plight of the native languages of the Americas. Of the hundreds of former Native American languages of North America, one-third are already extinct, another third have only a few old speakers, and only two (Navajo and Yupik Eskimo) are still being used for broadcast on local radio stations—a sure sign of trouble in this world of mass communications. Among the thousand or so native languages originally spoken in Central and South America, the only one with a secure future is Guarani, which along with Spanish is the national language of Paraguay. The sole continent with hundreds of native languages not already in dire straits is Africa, where most surviving native languages have tens of thousands or even millions of speakers, and where populations of small sedentary farmers currently seem to being holding on to their languages.