IELTS Academic Reading Practice Test 51

In the late 1940s, a chance conversation in a university corridor set in motion one of the most widely used technologies of the twentieth century. Bernard Silver, a graduate student at the Drexel Institute of Technology in Philadelphia, overheard a supermarket manager asking whether it would be possible to capture product prices automatically at the checkout. Silver mentioned the problem to his friend Norman Joseph Woodland, a former Boy Scout and graduate student with a strong interest in invention. Woodland became convinced that some pattern of dark and light markings could identify an object, and he began searching for a shape that could be read quickly and accurately from almost any angle.

Woodland later described how he thought of Morse code, whose dots and dashes had been used to send information for more than a century. Sitting in a chair and pushing his fingers into sand, he imagined the dots and dashes extended into thin and thick lines. The result was a circular symbol resembling a bullseye, together with a rectangular version made of vertical bars and spaces. In 1949 Woodland and Silver filed a patent for a 'Classifying Apparatus and Method', and it was granted in 1952. They sold the patent to the electronics company Philco for a modest sum, after which the technology passed through several hands and was developed further by other engineers.

Their earliest prototype used ultraviolet ink, but the marks faded and were expensive to produce, so they turned to visible printed lines. The first substantial commercial barcode system, however, was not used in shops but on the railways. In the 1960s the American railroad industry introduced a system called KarTrak that placed coloured reflective labels on the sides of freight cars. Trackside scanners read the labels as trains passed, allowing operators to track wagons automatically. Although thousands of railcars were eventually labelled, the system fell out of use because dust and ice made the labels difficult to read, and the colours faded in sunlight. The railway experiment nevertheless showed that automatic identification could work on a very large scale.

During the 1960s grocery executives became interested in barcodes as a way to speed up checkout queues and manage stock. A committee representing American supermarkets was formed to choose a single coding system, and several companies submitted designs. IBM gave the task to George Laurer, who built on Woodland's earlier rectangular concept. Laurer's design used a sequence of black bars and white spaces of varying widths to encode the digits from 0 to 9.

His version was accepted in 1973 as the Universal Product Code, or UPC. On 26 June 1974, a ten-pack of Wrigley's Juicy Fruit chewing gum became the first product to be scanned with a UPC code, at a Marsh supermarket in the town of Troy, Ohio. That pack of gum is now kept by the Smithsonian Institution as a piece of commercial history.

A barcode reader works by measuring reflected light. In a typical system, a laser or an LED shines light onto the symbol. The black bars absorb most of the light, while the white spaces between them reflect a large proportion back towards the reader. A photodetector receives the reflected light and converts the changing brightness into an electrical signal. A decoder then examines the widths of the bars and spaces and translates the pattern into a series of binary digits. The last digit in a UPC is a check digit, calculated from the earlier digits by a mathematical formula. When a product is scanned, the computer repeats the calculation to verify that the sequence has been read correctly. If the check fails, the scanner prompts the cashier to pass the item again.

Because one-dimensional barcodes store only a dozen or so digits, they do not contain the product name or its price. Instead, the code acts as a key that is sent to a stock database, where the relevant information is retrieved in milliseconds. This separation makes the system flexible: a price change can be made in the computer without reprinting labels. The same principle allows barcodes to be printed cheaply on almost any surface, from cardboard boxes to hospital wristbands. Barcode use spread rapidly through supermarkets in the late 1970s and early 1980s, and manufacturers soon printed the code directly on packaging rather than attaching separate labels.

The UPC code was adopted in North America, while European countries developed a related system known as the European Article Number, or EAN. The two systems were later harmonised so that scanners in most countries can read both formats. Many other symbologies have since appeared, including Code 128 for logistics and PDF417 for documents. These linear, or one-dimensional, codes hold limited information, so in the 1990s attention turned to two-dimensional formats. The QR code, invented in 1994 by the Japanese company Denso Wave to track parts in vehicle factories, can store hundreds of times more data in a square pattern of tiny black and white modules.

QR codes can be read by smartphone cameras, and because they can store text, web addresses or even payment details, they do not always require a central database. Yet the ordinary retail barcode has been remarkably durable. It remains one of the cheapest ways to identify goods reliably, and it is scanned billions of times each day across the world. From its Morse-code origins, the simple pattern of parallel lines has become an unnoticed background to modern trade.

The word monsoon comes from the Arabic mausim, meaning a season or a time of year, and it originally referred to the seasonal winds of the Arabian Sea. In the Indian Ocean region these winds reverse direction twice a year, and the reversal is linked to the contrasting ways in which land and sea respond to heat. During the northern summer, the land surface of South Asia becomes much warmer than the surrounding ocean, because rock and soil heat up more quickly than water. The warm air rises, creating a vast region of low atmospheric pressure, particularly over the Tibetan Plateau. This draws in moist air from the southern Indian Ocean and the Arabian Sea. As this air flows northwards it is deflected by the Earth's rotation and reaches the subcontinent as the wet south-westerly monsoon. In winter the land cools more than the sea, high pressure develops, and the winds reverse, producing the dry north-easterly monsoon.

The arrival of the monsoon is not a single event but a gradual advance of the rain-bearing front. A narrow band of cloud and rain known as the intertropical convergence zone, or ITCZ, shifts northwards over the subcontinent in early summer. Its leading edge, often called the monsoon trough, normally reaches the southern state of Kerala around the beginning of June. From there it moves north-west and north-east in fits and starts, occasionally pausing for days. By the middle of July the monsoon is usually established over most of India. The withdrawal follows a slower path, beginning in the north-west in September and retreating southwards through October and November.

Even after the monsoon has arrived, the quantity of rain varies greatly from place to place. Mountains have a powerful effect because they force the humid air to rise. As the air climbs, it cools and its moisture condenses into cloud and rain. The Western Ghats, a range running close to the south-western coast of India, receive extremely heavy rain on their windward slopes, while the plateau to their east lies in a rain shadow and remains comparatively dry. The village of Mawsynram, in the Khasi Hills of north-eastern India, is generally considered one of the wettest inhabited places on Earth, receiving an average of around 11,800 millimetres of rain a year. A short distance away the rainfall is dramatically lower.

The strength of the monsoon in any one year is strongly influenced by events thousands of kilometres away. El Niño, a periodic warming of the eastern and central Pacific Ocean, is often associated with weaker than normal monsoon rains over India, because it tends to shift the rising branch of the tropical circulation away from the Indian Ocean. La Niña, the opposite phase, usually has the reverse effect, bringing more rainfall. However, the relationship is not perfect. A pattern in the Indian Ocean itself, known as the positive Indian Ocean Dipole, can partly offset the drying effect of El Niño by delivering extra moisture. Other intraseasonal oscillations, such as the Madden–Julian Oscillation, cause the monsoon to move through active and inactive phases within the same season.

Airborne particles also play a role. Sulphate aerosols, which are produced by industry and scatter sunlight, tend to cool the surface and can weaken the land-sea temperature contrast that drives the monsoon. Black carbon from burning of wood and fossil fuels absorbs sunlight and warms the atmosphere, but its effect is complex and varies with height and location. Over South Asia the enormous quantities of pollution have the potential to alter rainfall patterns, although scientists disagree about how large the impact has been compared with natural variability.

Climate change adds further uncertainty. A warmer atmosphere can hold more moisture, so the same weather system may produce heavier downpours. Many climate models project that the South Asian monsoon will become more uneven: total rainfall may change little, but more precipitation may fall in brief, intense bursts, separated by longer dry spells. This would increase the risk of both floods and droughts. Trends already detected in some parts of South Asia are consistent with such a shift, but regional projections remain uncertain.

Forecasting the monsoon accurately is critical for farmers, water managers and governments. Modern methods combine satellite observations, ocean buoys and powerful computer models to predict the onset and overall strength of the rains. Yet the monsoon is a chaotic system, and forecasts beyond a few weeks are only probabilistic. Seasonal predictions are issued every year, but the public sometimes misunderstands a forecast of below-normal rainfall as a promise of drought. Scientists emphasise that reducing uncertainty and improving communication are as important as the models themselves.

A generation ago, linguists often spoke of the world's languages as a treasury that was being depleted. That image is now so familiar that it has almost lost its power. Of the roughly 7,000 languages still spoken today, many are endangered, and a common estimate is that at least one language ceases to be spoken every few weeks. The number of dialects is far larger, and their disappearance attracts less attention. In this essay I want to argue that dialect loss is a genuine cultural loss, but that the response must be careful: outsiders should not romanticise decline, and communities themselves must be the main decision-makers.

What counts as a dialect rather than a separate language? Linguists usually say that varieties are separate languages if their speakers cannot understand one another, but the boundary is rarely neat. Mutual intelligibility can be asymmetric, and politics often enters the picture. Speakers of Danish and Norwegian may follow each other reasonably well, yet the two are treated as different languages, while several mutually unintelligible varieties in China are nevertheless described as dialects of Chinese. Such labels are social as much as linguistic. This matters because calling something a dialect can imply that it is a lesser form of speech, when in fact every variety is a complete system with its own rules.

Dialects decline when the social conditions that support them change. Urbanisation brings people from different regions into close contact and often encourages them to switch to a standard or majority language in public life. Schools have historically taught a national standard and sometimes punished children for using local forms. Broadcasting and later the internet extended the reach of dominant languages, while internal migration and intermarriage made bilingualism common. Over a few generations, the local variety may become restricted to older people in private settings, then be used less and less by children. What begins as stigma can end as silence.

When a dialect disappears, something more than a set of words is lost. Oral literature, proverbs, songs and jokes rarely translate with their full effect. Local knowledge about plants, soils, animals and weather is often encoded in vocabulary and phrases that have no simple equivalent in the standard language. In some communities, traditional navigation or agricultural calendars depend on precise local terms. A dialect is also a mark of belonging; for many speakers it carries memories of childhood and family. These things do not appear in a census, which is why the loss can go almost unnoticed by outsiders.

Linguists have responded by documenting endangered speech. Teams of researchers make recordings of elderly fluent speakers, transcribe stories and conversations, and compile dictionaries and grammatical descriptions. Digital archives can preserve thousands of hours of audio for future study. Documentation is invaluable, but it cannot by itself keep a dialect alive. A recorded language is more like a museum specimen than a living community, because a living variety is used creatively by children and adapted to new situations. A grammar book may record the past, but it does not create new speakers.

Some communities have attempted to reverse the decline by giving local varieties a place in education, broadcasting and public life. In Wales, Welsh-medium schools and legal status have helped to slow and in places reverse the decline in the number of speakers. In New Zealand, Maori-language early childhood centres known as kōhanga reo have played a central role in revitalisation. Such programmes are expensive and require sustained political commitment, but where they are supported they can produce a new generation of active speakers. The examples are often cited as evidence that decline is not inevitable.

Yet not every community wants to revive a heritage dialect, and outside observers should be cautious about insisting that it should. For many speakers, moving to a standard language is a rational choice that brings access to education and employment. The loss of a dialect may be experienced as a genuine grief by some, while others regard it as a necessary step towards wider opportunities. Scholars who study endangered languages sometimes speak of the loss in terms of global ecological disaster, but the people directly involved are not exhibits. I believe the principle should be that communities have the right to choose the path that suits them, and the right to resources if they decide to pass their speech on.

None of this means that dialect loss does not matter. It does. But a sensible response must combine documentation of what is disappearing with realistic support for communities that wish to maintain their varieties. We should record, but we should not trap. We should assist, but we should not pressure. The disappearance of a dialect is often described as the death of a language. Perhaps a better metaphor is a family: a community whose members are deciding, under heavy pressure from the outside world, how much of their past to carry into the future.