Shadowing Practice: The Hunters: Sundews & the Venus Flytrap - Learn English Speaking with Video
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A plant that hunts.
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A leaf that snaps shut in a tenth of a second and counts to two before it does.
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This is not a single weird mutation in a single weird species.
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It is a whole family, a small one, that turned its leaves into traps and runs on electrical signals like a nerve.
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Welcome to Droseraceae.
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About 250 species, give or take.
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Almost all of them carnivorous, and almost all of them living where the soil is too poor to feed an honest plant.
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It is a small family doing something enormous.
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The famous one is the Venus flytrap, Dionea massipula, the leaf that closes in roughly 100 milliseconds.
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But the family also built the sundews, Drosera, which catch insects on sticky tentacles, and Aldrovanda, the water wheel plant,
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which does the fly trap trick underwater, with no roots at all.
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Three genera, three different traps, one impossible idea.
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Stop eating dirt and start eating the things that crawl across it.
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It is also the family that engineers study when they want a machine that grabs without a motor.
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Charles Darwin thought this family was wonderful.
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He spent years dropping bits of meat and egg onto sundew leaves and watching them curl.
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And in 1875, he published a whole book about it called Insectivorous Plants.
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He was right to be delighted.
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This is the family that proved a plant can move, can count, and can digest its own prey.
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all with no muscles and no brain.
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Let's start with the snap.
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The Venus Flytrap does not close because it is fast.
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It closes because it is loaded.
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The open trap is a leaf held concave, bent outward like a bowstring drawn and waiting.
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That shape is unstable.
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The leaf is storing elastic energy the way a spring stores it, and it is held there by turgor pressure,
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the water pressure that keeps every plant cell rigid.
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When the right signal arrives, the pressure changes, the leaf buckles, and it flips from concave to convex,
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from open to closed, in roughly 100 milliseconds.
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That is the fastest movement any plant makes.
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But the trap is not a hair trigger.
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Each half of the leaf carries a few trigger hairs, and a single touch does almost nothing.
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The plant needs two touches within about 20 seconds of each other before it will spend the energy to close.
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The two touches can land on the same hair or on different ones.
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A raindrop will not fool it because a raindrop does not struggle and it does not tap twice.
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One touch the plant remembers.
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A second touch it acts.
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A living timer with no clock.
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And if the second touch never comes, it forgets and resets.
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Once it closes, the trap narrows and only seals tight if it keeps feeling the prey move.
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Then it forms a sealed pocket, a kind of stomach, and the leaf opens again days later, empty.
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It is a counting plant, and what it is counting is electrical.
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A Venus flytrap fires an action potential, a spike of electrical voltage, the same kind of signal that fires down your own nerves.
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When an insect touches a trigger hair, ion channels in the cell membrane open, calcium floods in, and a voltage wave races across the leaf.
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This is the clearest demonstration we have that plants have excitable cells.
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They have no nerves and no brain, but they speak the same electrical language your neurons use.
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The first person to measure it was doctor named John Burden Sanderson who wired up a flytrap in the 1870s
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and watched the voltage jump.
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Two spikes, about 20 seconds apart, and the leaf buckles shut.
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The signal is all or nothing, just like a nerve, and a weak touch fires the same size spike as a strong one.
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The sensitive plant, mimosa, folds its leaves the same way, on the same kind of electrical fire engineers have noticed.
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The flytrap's snap is a bi -stable mechanism, a structure with two stable shapes that flips between them,
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and that is exactly the trick people want for soft robots.
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Copy the buckling leaf and a gripper can grab fast with almost no motor
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and almost no power because the leaf does the work and the energy is already stored.
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And if you put electrodes on a plant and read its action potentials, you have a living sensor,
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a plant cyborg that fires when it is touched or stressed or thirsty.
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Farmers are already wiring crops this way to catch drought before the wilt shows.
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The plant is already wired.
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We are just listening to it.
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The sun dews, Drosera, do not snap.
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They stick.
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A sundew leaf is covered in tentacles, each one tipped with a bead of glistening mucilage, the dew that gives the plant its name.
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To a fly, it looks like water or nectar.
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It is glue.
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The insect lands, touches a droplet and is caught.
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The nearby tentacles sense the struggle and slowly curl inward, holding over the prey and pressing it against the leaf.
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The movement is not fast, it is patient.
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A sundew can take hours to close around a fly.
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Then the leaf secretes enzymes, proteases that break down protein,
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phosphatases, esterases and the sundew digests its meal right there, on the surface and absorbs what it needs through the leaf itself.
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The whole leaf becomes a temporary stomach and when the meal is done, it resets, unfurls and waits for the next visitor.
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With roughly 240 species, Drusera is the most diverse group of carnivorous plants on Earth and it grows on every continent except Antarctica.
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Australia is its great stronghold, with species that survive dry summers as underground tubers.
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Darwin called the sundew one of the most wonderful plants in the world.
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The chemists have noticed too.
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The same digestive enzymes and the same wet, sticky, self -cleaning surface are exactly the properties people want for biomimetic materials,
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adhesives that grip, digest, and let go without leaving a residue.
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And then there is the family's strangest member, Aldrovanda vesculosa, the waterwheel plant.
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It is a Venus flytrap that gave up on land.
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It lives underwater, floating free,
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with no roots at all and its traps are tiny snap traps strung along a stem like the blades of a wheel,
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which is where the name comes from.
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Each trap is only a few millimeters across, and it snaps shot on small aquatic creatures, water fleas and mosquito larvae,
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in a fraction of a second.
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It is among the fastest movements any plant makes underwater.
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Same family, same snap, a different medium.
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With no roots, Aldrovanda takes its minerals straight from the prey it catches.
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It overwinters as a tight little bud called a turian resting on the bottom until the water warms.
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What is remarkable is that the snap trap evolved more than once, even within this one small family.
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Dianaea on land, Aldravanda in the water, and the flypaper trap of the sundews is a third design entirely.
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Three genera reinventing the trap again and again, as if the family could not stop solving this same problem.
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Aldravanda is a single species, and it is now rare, scattered across the old world and declining almost everywhere it still survives.
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It has already vanished from large parts of its old range.
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Carnivory, though, is not a Drosaraceae invention.
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It evolved independently, over and over, in at least six separate lineages of flowering plants.
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The tropical pitcher plants, Nepenthes, belong to a separate family, Nepenthesae.
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The American pitcher plants, the trumpet pitchers of Saracenia, the cobra lily, Darlingtonia, the sun pitchers,
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Heliamphora, belong to another separate family, Saraseniaceae.
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The Australian pitcher plant, Cephalotus, sits in a family of its own.
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And the corkscrew plants, Genlicia, and the bladderworts, Utricularia, are yet another family,
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Lentibulariaceae, with traps that suck prey in underwater.
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Different ancestors, different traps, the same answer.
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Why does it keep paying?
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Because these plants do not live where food is easy.
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They live in bogs, wet, acidic, nutrient -poor ground, where the nitrogen and phosphorus a plant needs are locked away or washed out.
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A normal plant starves there.
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A plant that can fly trap or glue trap or pitfall trap the insects wandering through gets its minerals from the air.
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One bug at a time time.
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It still photosynthesizes for energy.
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The trap is not for calories.
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It is for fertilizer.
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But carnivory is not free.
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Building a trap and making digestive enzymes costs the plant something.
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So it only pays where the soil is poor and the sun and water are good enough to keep the leaf alive.
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And the pitcher plants do not even move.
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They just wait with a pitfall full of fluid at the bottom of a slippery tube.
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The worse the dirt, the better the trap has to be.
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Which is exactly why convergent carnivory is not an accident.
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It is a solution that evolution keeps arriving at.
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And here is the part that should not be true.
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The Venus flytrap, the most famous carnivorous plant in the world is native to a range you can almost drive across in an afternoon.
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It grows wild in a thin strip of the Carolinas, within about 75 miles of Wilming to North Carolina,
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and in a sliver of South Carolina beside it.
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That is almost the entire wild range of the species.
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And it is being stolen.
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Wild flytraps are dug up by the thousands and sold because a poached plant is cheaper than a grown one.
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In North Carolina, digging them up is a felony, and still they disappear.
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On top of that, the bogs they need are drained, paved, and fire -suppressed until there is nothing left to come back to.
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The flytrap depends on fire the way a pine forest does to clear the competition and let the bog stay open.
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By any honest accounting, it is an endangered plant, protected by law and still declining,
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with a wild population that is a small fraction of what it once was.
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So here is the only ask.
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If you want a Venus flytrap, buy one that was grown in a nursery.
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There is no reason to buy a wild one.
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Nurseries propagate these plants by the millions, by tissue culture, for a few dollars each, and a cultivated flytrap is healthier,
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legal, and not stolen out of a bog.
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If you ever see one in the wild, look, take a photograph, and leave it exactly where it is.
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The plant that eats insects should not be eaten by us.
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Subscribe.
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There is a lot more weirdness down here.
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Vocabulario y notas de pronunciación para esta lección
Esta lección de conversación se basa en el vídeo “The Hunters: Sundews & the Venus Flytrap”. Las palabras que más se repiten: plant, trap, leaf, flytrap, snap. Este vídeo tiene 141 frases y 1774 palabras para practicar shadowing. La parte hablada dura 12:24. El hablante mantiene un ritmo constante de unas 143 palabras por minuto, cómodo para el shadowing. Solo el 71 % de las palabras está entre las 3.000 más comunes del inglés, por lo que el vocabulario es exigente.
Vocabulario clave de este vídeo
15 palabras del vídeo que vale la pena aprender, con su pronunciación y significado:
| Palabra | Pronunciación | Significado |
|---|---|---|
| trap sustantivo | /tɹæp/ | trampa, cepo |
| leaf sustantivo | /lif/ | hoja, foja (desus.) |
| snap verbo | /snæp/ | quebrar, romper de golpe |
| prey sustantivo | /pɹeɪ/ | presa |
| insect sustantivo | /ˈɪn.sɛkt/ | insecto |
| nerve sustantivo | /nɝv/ | nervio |
| underwater adjetivo | /ʌndɚˈwɔtəɹ/ | sumergido, subacuático |
| wire sustantivo | /ˈwaɪɚ/ | alambre, hilo |
| roughly adverbio | /ˈɹʌf.li/ | toscamente |
| trigger sustantivo | /ˈtɹɪɡɚ/ | gatillo, perrillo |
| voltage sustantivo | /ˈvəʊltɪd͡ʒ/ | voltaje, tensión |
| spike sustantivo | /spaɪk/ | clavo, pincho |
| enzyme sustantivo | /ˈɛn.zaɪm/ | enzima |
| digest verbo | /daɪˈd͡ʒɛst/ | digerir |
| buckle sustantivo | /ˈbʌkəl/ | hebilla |
Phrasal verbs que vas a escuchar
| Palabra | Significado |
|---|---|
| break down verbo | descomponerse, averiarse |
Gramática en este vídeo
Las estructuras que más usa el hablante, con las palabras exactas del vídeo:
| Estructura | En el vídeo |
|---|---|
| Voz pasiva be + participio pasado — importa lo que ocurre, no quién lo hace | is loaded · is held · is already stored |
| Present perfect have/has + participio pasado — una acción pasada que sigue importando ahora | have noticed · has already vanished |
Pronunciación a tener en cuenta
- Los sonidos de “th”: thin /ˈθɪn/, tenth /tɛnθ/, thirsty /ˈθɝs.ti/
- Los sonidos de “sh” y “zh”: fraction /ˈfɹæk.ʃən/, wash /wɑʃ/, evolution /ˌiːvəˈluːʃ(ə)n/, tissue /ˈtɪʃ.(j)u/, demonstration /dɛmənˈstɹeɪʃən/
- Palabras largas — cuida el acento: electrical /ɪˈlɛktɹɪkəl/, underwater /ʌndɚˈwɔtəɹ/, temporary /ˈtɛmp(əˌɹ)ɛɹi/, evolution /ˌiːvəˈluːʃ(ə)n/, mechanism /ˈmɛk.ə.nɪ.zəm/
Sonidos difíciles para hispanohablantes:
- s + consonante al inicio — sin añadir una “e” delante: snap /snæp/, spike /spaɪk/, stable /ˈsteɪ.bəl/, stomach /ˈstʌmək/, steal /stiːl/
- /v/ — no es /b/: los dientes tocan el labio inferior: nerve /nɝv/, voltage /ˈvəʊltɪd͡ʒ/, arrive /əˈɹaɪv/, evolve /ɪˈvɑlv/, sensitive /ˈsɛn.sɪt.ɪv/
- /z/ — sonora, no /s/: enzyme /ˈɛn.zaɪm/, mechanism /ˈmɛk.ə.nɪ.zəm/, visitor /ˈvɪzɪtɚ/, residue /ˈɹɛzɪduː/, esterase /ˈɛstəreɪz/
Cómo practicar con este vídeo
- Escucha el vídeo entero una vez sin hablar y anota las palabras que no conoces.
- Haz shadowing frase por frase a velocidad normal, repitiendo cada una hasta que tu ritmo coincida con el del hablante.
- Grábate y compara con el original, prestando atención a palabras como trap, leaf, snap.
¿Qué es la Técnica de Shadowing?
Shadowing es una técnica de aprendizaje de idiomas respaldada por la ciencia, desarrollada originalmente para la formación de intérpretes profesionales y popularizada por el políglota Dr. Alexander Arguelles. El método es simple pero poderoso: escuchas audio en inglés nativo y lo repites en voz alta de inmediato, como una sombra que sigue al hablante con solo 1-2 segundos de retraso. A diferencia de la escucha pasiva o los ejercicios de gramática, el shadowing obliga a tu cerebro y músculos de la boca a procesar y reproducir simultáneamente patrones de habla reales. Las investigaciones muestran que mejora significativamente la precisión de la pronunciación, la entonación, el ritmo, el habla conectada, la comprensión auditiva y la fluidez al hablar, convirtiéndola en una de las metodologías más efectivas para la preparación del IELTS Speaking y la comunicación en inglés en el mundo real.