IELTS Academic Reading Practice Test 18

A Roughly 7,000 distinct languages are currently spoken in the world. By the most widely cited projections, between a third and a half of these will, in many linguists' view, fall out of everyday use by the end of the twenty-first century. Each lost language is widely said to represent a complete system for understanding the world — a vocabulary refined over generations, grammatical constructions that may have no parallel elsewhere, and a record of cultural and ecological knowledge that disappears with the last fluent speakers. The disappearance of a language is therefore widely treated as comparable in significance to the extinction of an entire species, with similar irreversibility and similar consequences for the diversity of the human inheritance.

B The geography of language loss is regarded as uneven. Areas of greatest linguistic diversity — including New Guinea, sub-Saharan Africa, parts of the Amazon, and the highlands of southern Mexico — are also among the regions losing languages most quickly. Pressures driving extinction typically include economic incentives to speak dominant national languages, formal-education systems that ignore minority languages, urban migration that scatters speech communities, and explicit official discouragement of minority languages in many states. The combination of these pressures is widely said to be self-reinforcing: once a language stops being used outside the home, the next generation generally has weaker reasons to acquire it, and within two or three generations the language may move from full vitality to functional silence.

C The threshold of intergenerational transmission is widely considered the key indicator of language vitality. A language with thousands of elderly speakers but no children acquiring it is, in functional terms, generally said to be on the path to extinction. Sociolinguist Joshua Fishman developed in the early 1990s an eight-stage scale for language endangerment, with the most threatened languages at stage seven or eight, where only elderly speakers remain. UNESCO's Atlas of the World's Languages in Danger refines this scheme and currently lists more than 2,500 languages as endangered or critically endangered. Surveys of intergenerational use in households are widely said to be the single most informative measurement that linguists can take of a language's future.

D Revitalisation efforts have, according to many researchers, produced varied results. The most striking success is widely said to be Hebrew, which moved from being almost exclusively a religious and literary language in the late nineteenth century to the everyday vernacular of millions in twenty-first-century Israel. Welsh has, in researchers' view, experienced a substantial revival driven by state policy, including bilingual education and Welsh-language broadcasting; the proportion of Welsh speakers in Wales has stabilised or modestly grown since the 1990s. Māori in New Zealand has seen the launch of Kohanga Reo — language nests in which preschool children are immersed in Māori by elderly fluent speakers — and broad cultural revitalisation initiatives. The successful cases are widely said to share active state support, accessible institutions for transmission, and cultural pride that motivates new learners to maintain proficiency through adulthood.

E Documentation programmes have, in many linguists' view, grown to preserve what cannot be revived. Projects including the Endangered Languages Documentation Programme at SOAS in London, the Linguist List's archive, and similar institutional efforts at Berkeley, the Australian Institute of Aboriginal and Torres Strait Islander Studies, and the Max Planck Institute have produced extensive recordings of endangered languages, often working with elderly last speakers. The resulting archives generally provide source material for future scholarship and, in some cases, for community efforts to revive languages whose last speakers have died.

F The relationship between language and traditional ecological knowledge has become a major topic of interest. Specialised vocabularies for local plants, animals, weather patterns, and seasonal cycles are widely said to be deeply integrated with language structure in ways that translation cannot fully preserve. When a language is lost, the conceptual organisation of this knowledge goes with it, even if individual facts can be recorded. This has, in researchers' view, contributed to growing recognition that language preservation is connected to broader efforts to maintain biodiversity and traditional knowledge systems.

A The world's oceans are widely regarded as not still bodies of water but a dynamic, interconnected circulation system that moves heat, nutrients, and dissolved gases across the planet. The major ocean currents — both shallow wind-driven gyres and deep buoyancy-driven flows — together typically transport more heat from the equator toward the poles than the atmosphere does, in researchers' view profoundly shaping global climate. Disruptions to these currents would, according to many oceanographers, reshape the climate of entire continents within decades. The very fact that European cities at the same latitude as Hudson Bay are temperate rather than sub-Arctic is widely cited as a direct everyday consequence of this oceanic heat transport.

B Surface currents are driven principally by prevailing winds and the Coriolis effect arising from Earth's rotation. The result is widely said to be a system of great rotating gyres in each ocean basin: the North Atlantic Gyre, the North Pacific Gyre, and corresponding gyres south of the equator. Western boundary currents within these gyres, such as the Gulf Stream off the eastern United States and the Kuroshio off Japan, are particularly strong and warm, carrying tropical heat poleward. Eastern boundary currents along the western coasts of continents — the California Current, the Humboldt Current — bring cooler water from higher latitudes back toward the equator. The contrast between the two flanks of each gyre is widely said to produce dramatic differences in coastal climate at the same latitudes.

C The deep ocean circulation, sometimes called the thermohaline circulation or the global conveyor, is widely said to be driven by differences in density rather than wind. Water becomes denser when it cools, and when salt is added by evaporation or by sea-ice formation. In a few specific regions — the North Atlantic near Greenland, and around Antarctica — surface water becomes dense enough to sink to the deep ocean. The resulting flow is regarded as one of the slowest motions on the planet, with water that sinks in the North Atlantic taking roughly a thousand years to return to the surface elsewhere. The slowness of the conveyor is widely said to give it a memory of past climate states stretching back centuries, with measurable consequences for present circulation patterns.

D Currents matter biologically as well as climatically. Upwelling currents — including the Humboldt off Peru and the Benguela off southwestern Africa — bring deep nutrient-rich water to sunlit surface layers, supporting some of the most productive fisheries on Earth. The El Niño-Southern Oscillation, which periodically weakens Pacific upwelling, is widely said to be capable of collapsing Peruvian anchovy fisheries and reshaping weather patterns across the tropical Pacific. Coral reef ecosystems generally depend on consistent current patterns to transport reef larvae between reefs and to maintain water temperatures within tolerable ranges.

E Climate change has, in researchers' view, begun to affect the major currents. Freshwater inflow from melting Greenland ice is freshening parts of the North Atlantic, slowing the sinking that drives the Atlantic Meridional Overturning Circulation. Observational data and modelling both broadly suggest the circulation has weakened by perhaps 15 percent since the mid-twentieth century, with substantial uncertainty about future evolution. A substantial shutdown of the circulation would, in many researchers' view, dramatically cool northwestern Europe and shift tropical rainfall patterns — though such an event is widely said to remain a tail risk rather than a near-term certainty. Several recent studies have, in researchers' view, narrowed the range of uncertainty but stopped well short of confident prediction one way or the other.

F Plastic and other floating pollution accumulates at the centres of the great surface gyres, producing what are sometimes called garbage patches. The Great Pacific Garbage Patch, the largest, is widely said to contain an estimated 80,000 tonnes of floating plastic spread over an area larger than France. The patches are not solid masses but dispersed suspensions, ranging from fragments visible at the surface to microplastics suspended in the water column. Cleanup attempts, including the Ocean Cleanup project, have so far recovered only a tiny fraction of the total, and the volume continues to grow with continuing input from coastal regions.

A The objects that fill the world's museums and historical collections reportedly face a continuous, slow battle against the physical and chemical processes that would, given enough time, destroy them. Conservation — the scholarly discipline concerned with preserving, examining, and where necessary stabilising cultural and natural-history objects — has, in researchers' view, evolved from a craft tradition rooted in restoration into a science-based field that draws on chemistry, physics, materials science, and increasingly digital technology. The change in conceptual emphasis from restoring objects to a perceived former state toward understanding and slowing their natural ageing is widely said to be one of the most important shifts of the past century in museum practice.

B Conservation in its modern form is widely said to have developed substantially after the First World War, when the Department of Scientific Research was established at the British Museum in 1920. The discipline matured through the establishment of dedicated institutions including the Istituto Centrale per il Restauro in Rome in 1939 and the International Centre for the Study of the Preservation and Restoration of Cultural Property — ICCROM — founded in 1959 as a UNESCO-sponsored body. The Western emphasis on minimal intervention, reversibility of conservation treatments, and clear documentation has, in researchers' view, become accepted internationally, though some traditions reportedly place greater weight on restoring objects to perceived original appearance. The methodological differences between Western minimal-intervention practice and more interventionist traditions are widely said to be the subject of ongoing professional discussion.

C The conservation of paper, parchment, and textiles is widely regarded as among the oldest and best-developed specialisms. Paper degrades through oxidation of cellulose, hydrolysis catalysed by acidic compounds from inks and atmospheric pollutants, and the colonisation of moulds in humid conditions. The deacidification of archives and books, in which alkaline solutions are introduced to neutralise residual acid, has been practised since the 1970s. Modern approaches typically use mass-deacidification machines that can treat entire books with minimal handling. Storage at controlled humidity around 50 percent and temperature around 18 degrees Celsius generally substantially slows further deterioration.

D Painting conservation has, in researchers' view, its own demanding methods. Removing layers of darkened varnish from oil paintings without disturbing the underlying paint requires careful solvent chemistry. Cleaning the Sistine Chapel ceiling between 1980 and 1989 was, according to many art historians, both technically ambitious and publicly controversial, revealing brighter, more contrasted Michelangelo paintings beneath centuries of soot and old restoration. Subsequent technical analyses have used X-ray fluorescence and infrared reflectography to map paint layers and underdrawings non-destructively, providing information about an artist's technique that would once have required physical sampling. Such non-destructive techniques are widely said to be central to current practice because they preserve the integrity of the object while still producing the scientific data required for informed treatment decisions.

E The conservation of natural-history specimens presents specific challenges. Skin preparations and stuffed animals from the eighteenth and nineteenth centuries were often treated with arsenic-based preservatives that prevented insect damage but now reportedly pose health and ethical concerns for handlers. Wet specimens — fish, amphibians, and reptiles preserved in alcohol — must be regularly checked for fluid loss and contamination. The famous bone collection of Berlin's Museum für Naturkunde is widely said to have survived the Second World War in a basement; many specimens elsewhere did not, and the loss of irreplaceable type specimens is, in researchers' view, one of the lasting scientific consequences of twentieth-century conflicts.

F Digital methods are widely described as transforming the field. Three-dimensional scanning at sub-millimetre resolution now allows objects to be documented in such detail that physical handling can be substantially reduced for both research and exhibition. Online repositories generally make scans of significant artefacts available to scholars worldwide; some objects too fragile to display can be experienced as detailed virtual replicas. Machine-learning systems are being applied to detect early signs of deterioration in paintings and manuscripts by spotting subtle changes between time-separated images. These tools complement rather than replace skilled conservators, but they are widely said to substantially extend what is practical.

G Climate change is widely said to present a new set of challenges. Coastal museums reportedly face flood risk; the British Museum and the Smithsonian have both undertaken planning for sea-level rise and extreme weather. Archaeological sites in permafrost-rich regions are now actively degrading as the ground that has preserved them for millennia thaws. Wooden ships and structures in cold-water harbours are widely said to be showing increased decay as warmer waters allow wood-boring marine organisms to extend their range northward. Conservation as a discipline is, in researchers' view, increasingly framing its work as part of broader heritage-protection responses to climate change.