“Hello” is a relatively new greeting. It first appeared sometime in the mid-1800s, but many people would not have dreamed of using it. “Hello” was considered a very impolite way to greet someone. Instead, people used formal expressions like “How do you do?”

Back then, there were several words that sounded like “hello,” but they were used to get someone’s attention or to express surprise. For example, if you caught your little brother stealing your snack, you might have said, “Halloa there! Stop eating my cheese!” If you found a fly in your soup, you might have shouted, “Hullo! How did that get in there?”

Everything started to change in 1876, when Alexander Graham Bell invented the telephone. The first telephones didn’t have numbers you could dial, nor did they have bells or ringers. Instead, your telephone sent signals along telephone lines to a central office where an operator would answer by saying something like “Are you there, sir?” or “What is wanted?” The operator would then connect your phone to the phone of the person you wanted to reach. There was just one small problem: Since telephones didn’t ring, how would the person you were calling know that you were “on the line”? The answer is you would yell (大喊) into your phone and hope someone on the other end heard you. But what would you yell? And what would the person you were calling say when they were going to answer? Bell suggested “Ahoy! Ahoy!” but it didn’t catch on. Then the famous inventor Thomas Edison suggested the word hello. That caught on right away.

“Hello” became so popular that by 1878 telephone operators were required to use it. In fact, operators received the nickname (绰号) “Hello Girls.” Soon, “hello” became not just the standard way to answer the phone, but an accepted way to greet people in person.

Buttons are found on all sorts of clothing. They are usually small and round and made of metal or plastic. They fasten, or connect, one piece of clothing to another. They make sure your clothes don’t fall off. Some buttons can be beautiful and even have very fine details. But are they cute? Babies are often described as cute as a button. Language experts don’t know why. But we do know more about two other button expressions: button-down and buttoned-up.

Men or women often wear button-down shirts to the office. As an adjective button-down means being conservative (保守的)or traditional. People described as buttoned-down stay as close as possible to the normal way of dressing and behaving. People and events can both be described as buttoned-down. We should note here that as an adjective you can either say “buttoned-down” or “button-down”.

However, the adjective buttoned-up is a little different. If someone is buttoned-up, he seems very businesslike. In personal relationships, a buttoned-up person is cold and indifferent, meaning they physically and emotionally keep away from others.

There are many other ways “button” is used as a verb. When you fasten a button, you can also just say “button a button”. So, you can say lo a friend, “Hey, your top button is unbuttoned. You should button it.”

When buttoning a billion you slip it into a buttonhole. A buttonhole traps the button. So, lo buttonhole someone means you have trapped them into a spoken conversation. Now, let’s say you find yourself buttonholed in a conversation at a party. The person just keeps talking and talking and talking! Finally, you can’t stand it any longer. You tell the person to button it! “Button your lip” is another equally rude but effective way to stop a person who talks too much.

Another kind of difficult person is someone who pushes your buttons. To push someone’s buttons means you know exactly how to get that person angry or upset. People who push the panic button are not as dislikable as button-pushers. However, they can be tiring to others. In a crisis, it is important to remain calm. Pushing the panic button can make an already tense situation worse.

Charles Darwin found inspiration for his theory of evolution in birds' beaks, giant tortoise shells — and language. “The survival or preservation of certain favored words in the struggle for existence is natural selection, he wrote in The Descent of Man in 1871.

Language gradually shifts over time. Much research examines how social and environmental factors influence language change, but very little wrestles with the forces of human cognitive (selection that fix certain words into the vocabulary. For an extensive new study, published in the Proceedings of the National Academy of Sciences USA, scientists investigated just that.

The scientists carried out two experiments and the results combine to show three properties that give words an “evolutionary advantage” by helping them stick in the brain: First, words typically acquired at an early age such as “hand” or “today”) are stabler. Next, concrete words linger better than abstract ones: “dog” lasts longer than “animal,” which lasts longer than “organism.” Lastly, emotionally exciting words — whether negative or positive — tend to last.

Early language-evolution models assumed that language becomes increasingly complex over time. But this new study supports a more recent theory that language ultimately gets more efficient and easier to understand.

The proposed trend toward “simpler” language is controversial. Columbia University linguist John MeWhorter more or less agrees with the study's results about evolutionary advantages within language. He questions, however, implications regarding the overall efficiency of English — a language he says contains things like “needlessly complex” grammatical traces.

Study lead author Ying Li, a psychologist at the Chinese Academy of Sciences and a non-native English speaker, notes that English had even more puzzling grammar in the past. MeWhorter, Li supposes, “would complain more if he traveled back 800 years ago.”