Why Is It 'Eleven, Twelve' Instead of 'Oneteen, Twoteen'?

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IStock

English number words are pretty logical after a point. From twenty-one to ninety-nine, the same principle applies: you say the tens place followed by the units place. But the teens are different. Not only does the ten (which is where the word teen comes from) come after the units place (10+7 is not teen-seven but seventeen), eleven and twelve don't fit in at all.

Eleven and twelve come from the Old English words endleofan and twelf, which can be traced back further to a time when they were ain+lif and twa+lif. So what did this –lif mean? The best guess etymologists have is that it is from a root for "to leave." Ainlif is "one left (after ten)" and twalif is "two left (after ten)."

So then the question is, why don't we have threelif, fourlif, fiflif, sixlif and so on? The answer has to do with the development of number systems over history. A long, long time ago, when the number words were first being formed, most people didn't have much reason to distinguish numbers above ten. In fact, some languages of primitive cultures only have number words for one, two, and many. So the basic number words up to ten formed first, then they were extended a bit with the –lif ending.

Maybe there was a threelif, fourlif type system, but 11 and 12 were used more often in daily life. Many number systems are based on 12 because it's divisible by the most numbers, and because you can count to 12 on one hand by using your thumb to count three knuckles on each of the other fingers. (We have the word dozen because 12 is so useful). If 11 and 12 are being used more frequently, the forms for them will stick, even when another system starts to develop. 

You can extend that idea to other number words. We have more irregularities of pronunciation in the tens (twenty, thirty, fifty instead of twoty, threety, fivety) because we've been making everyday use of those numbers for longer than we have for two hundred, three hundred, and five hundred). Thousand is an old word, but its original sense was "a great multitude," a non-numerically-specific, but very useful idea. The words we needed earliest, and used the most frequently are usually the most irregular.

So the short answer is, we created words for 11 and 12 a long time ago by calling them "one left after ten" and "two left after ten." They were more useful to us than the higher numbers, so we said them more and they became a habit that we couldn't shake.

Kids always notice the weird bits about language better than grownups. Thanks to five-year-old Katie English for this fabulous question!

See Also...

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Why Does Hand Sanitizer Have an Expiration Date?

Hand sanitizer does expire. Here's why.
Hand sanitizer does expire. Here's why.
galitskaya/iStock via Getty Images

The coronavirus pandemic has turned hand sanitizer from something that was once idly tossed into cars and drawers into a bit of a national obsession. Shortages persist, and people are trying to make their own, often to little avail. (DIY sanitizer may not be sterile or contain the proper concentration of ingredients.)

If you do manage to get your hands on a bottle of Purell or other name-brand sanitizer, you may notice it typically has an expiration date. Can it really go “bad” and be rendered less effective?

The short answer: yes. Hand sanitizer is typically made up of at least 60 percent alcohol, which is enough to provide germicidal benefit when applied to your hands. According to Insider, that crucial percentage of alcohol can be affected over time once it begins to evaporate after the bottle has been opened. As the volume is reduced, so is the effectiveness of the solution.

Though there’s no hard rule on how long it takes a bottle of sanitizer to lose alcohol content, manufacturers usually set the expiration date three years from the time of production. (Because the product is regulated by the Food and Drug Administration, it has to have an expiration date.)

Let's assume you’ve found a bottle of old and forgotten sanitizer in your house somewhere. It expired in 2018. Should you still use it? It’s not ideal, but if you have no other options, even a reduced amount of alcohol will still have some germ-fighting effectiveness. If it’s never been opened, you’re in better shape, as more of the alcohol will have remained.

Remember that sanitizer of any potency is best left to times when soap and water isn’t available. Consider it a bridge until you’re able to get your hands under a faucet. There’s no substitution for a good scrub.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

Why Are Sloths So Slow?

Sloths have little problem holding still for nature photographers.
Sloths have little problem holding still for nature photographers.
Geoview/iStock via Getty Images

When it comes to physical activity, few animals have as maligned a reputation as the sloth. The six sloth species, which call Brazil and Panama home, move with no urgency, having seemingly adapted to an existence that allows for a life lived in slow motion. But what makes sloths so sedate? And what horrible, poop-related price must they pay in order to maintain life in the slow lane?

According to HowStuffWorks, the sloth’s limited movements are primarily the result of their diet. Residing mainly in the canopy vines of Central and South American forests, sloths dine out on leaves, fruits, and buds. With virtually no fat or protein, sloths conserve energy by taking a leisurely approach to life. On average, a sloth will climb or travel roughly 125 feet per day. On land, it takes them roughly one minute to move just one foot.

A sloth’s digestive system matches their locomotion. After munching leaves using their lips—they have no incisors—it can take up to a month for their meals to be fully digested. And a sloth's metabolic rate is 40 to 45 percent slower than most mammals' to help compensate for their low caloric intake. With so little fuel to burn, a sloth makes the most of it.

Deliberate movement shouldn’t be confused for weakness, however. Sloths can hang from branches for hours, showing off some impressive stamina. And because they spend most of their time high up in trees, they have no need for rapid movement to evade predators.

There is, however, one major downside to the sloth's leisurely lifestyle. Owing to their meager diet, they typically only have to poop once per week. Like going in a public bathroom, this can be a stressful event, as it means going to the ground and risking detection by predators—which puts their lives on the line. Worse, that slow bowel motility means they’re trying to push out nearly one-third of their body weight in feces at a time. It's something to consider the next time you feel envious of their chill lifestyle.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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