The word “ OK”, the most frequently spoken expression on the planet, celebrated its 178th anniversary (周年纪念日) on March 23.

Henry Nass, a 66-year-old retired English teacher, had spent the last few weeks handing out cards supporting “ Global OK Day” in advance of the coming anniversary.

The term “ OK” was born in the 19th century. Late etymologist Allen Walker Read found the twoletter word in 1839, when editors at The Boston Morning Post signed off on articles as “ all correct” with an “ OK” or “ oll correct”.

The word made it into print on March 23 of that year in an article against an editor in Providence who had said, wrongly, that a group of Bostonians heading for New York would pass through the Rhode Island capital. “We didn’t say a word about our group passing through the city of Providence,” The Boston Morning Post reported. “O. K. — all correct.”

The humour of the Providence-Boston joke has been lost to history — but the word OK took off from there, soon meaning agreement, acceptance, satisfaction, quality or likability. In 1840, it served as a slogan (口号) for President Martin Van Buren’s unsuccessful re-election campaign. OK was picked up by telegraph operators as an easy abbreviation (缩写词) to say they received transmission. “Buzz Aldrin’s first words spoken on the moon were ‘ OK. Engine stop,’” says Allan Metcalf, author of “OK: The Improbable Story of America’s Greatest Word”.

Modern texting has produced a new generation of abbreviations — BTW (by the way) and LOL (laugh out loud) among them, but none has replaced OK. That’s why many people support the English teacher’s call for an OK birthday celebration.

“We happen to know the exact date and place of the very first OK and that’s not very usual for many words, so why not celebrate that day?” says Metcalf.

Human speech contains more than 2,000 different sounds, from the common “m” and “a” to the rare clicks of some southern African languages. But why are certain sounds more common than others? A ground-breaking, five-year study shows that diet-related changes in human bite led to new speech sounds that are now found in half the world’s languages.

More than 30 years ago, the scholar Charles Hockett noted that speech sounds called labiodentals(唇齿), such as “f” and “v”, were more common in the languages of societies that ate softer foods. Now a team of researchers led by Damián Blasi at the University of Zurich, Switzerland, has found how and why this trend arose.

They discovered that the upper and lower front teeth of ancient human adults were aligned(对齐), making it hard to produce labiodentals, which are formed by touching the lower lip to the upper teeth. Later, our jaws changed to an overbite structure(结构), making it easier to produce such sounds.

The team showed that this change in bite was connected with the development of agriculture in the Neolithic period. Food became easier to chew at this point. The jawbone didn’t have to do as much work and so didn’t grow to be so large.

Analyses of a language database also confirmed that there was a global change in the sound of world languages after the Neolithic age, with the use of “f” and “v” increasing remarkably during the last few thousand years. These sounds are still not found in the languages of many hunter-gatherer people today.

This research overturns the popular view that all human speech sounds were present when human beings evolved around 300,000 years ago. “The set of speech sounds we use has not necessarily remained stable since the appearance of human beings, but rather the huge variety of speech sounds that we find today is the product of a complex interplay of things like biological change and cultural evolution,” said Steven Moran, a member of the research team.

In July 1915, sick James Murray, one of the early editors of the Oxford English Dictionary (OED), defined one final word. He had devoted 36 years to the dictionary. Knowing he would not see the project complete, he wrote his last entry: for “twilight”.

The story of Murray’s final days is one of many memorable tales in “The Dictionary People”. Conceived (构思) in 1857, the OED was a huge crowdsourcing project comprising 3,000 people. The idea was to create a “descriptive” dictionary that tracked words’ use and meaning over time. Volunteers read widely, mailing in examples of how “rare, old-fashioned, new” words were used. What is surprising about this random method is that it worked, achieving order through the large number of contributors.

The origin story of Sarah Ogilvie’s book is almost as improbable as that of the dictionary itself. Ms Ogilvie, an editor for the OED, went into the archives (档案馆) of Oxford University Press and came across an old notebook. It had belonged to Murray and contained the names and details of the dictionary volunteers, most of whom had previously been unknown. “The Dictionary People” is her work of detective scholarship, presenting the lives behind the names.

The dictionary’s contributors are an engaging cast, including one of Karl Marx’s daughters and J. R. R. Tolkien. For some, the dictionary was something addictive: one contributor supplied 165,061 quotations. Murray, too, was assiduous. He once wrote to George Eliot to ask about a word choice in “Romola”, published 17 years earlier.

Ms Ogilvie’s book is full of strange but interesting tales. Many dictionary lovers engaged in another crowdsourcing fashion: collecting and measuring rainwater. The presentation of the book is irregular, too, taking its structure from the work it describes. For example, in her first chapter, “A for Archaeologist (考古学家),” she relates the early life of Margaret A. Murray, a pioneering Egyptologist. There are 26 alphabetical (按字母顺序排列的) chapters, each celebrating a group of contributors. This is a clever concept.