Susie Dent: Chopsing or jaffocking, why Brits are thrilled by wordplay

As a new Radio 4 quiz show begins, Countdown lexicographer Susie Dent explains a love affair

Britain's fascination with its changing language is renowned. Unlike our neighbours on the mainland of Europe, we have resisted creating an academy to legislate over proper English. We each have our linguistic bugbear, but few of us would want to freeze our mother tongue. Even Dr Johnson realised that his hope of keeping pure the English he adored was a futile proposition: "To enchain syllables, and to lash the wind, are equally the undertakings of pride."

One of the joys of language is its constant evolution, and a lexicographer's job is both to track new words and to reassess those from the past. Tomorrow, Radio 4 will bring a rich assortment of both to its listeners in the show Wordaholics, hosted by my Countdown colleague Gyles Brandreth. The series will have Gyles and his guests exploring the meaning of such tantalising words as "Flemish eye", "knock-knobbler", and "gavelock".

For the past 12 months, I've been steeped in obscure and forgotten words, for two reasons. The first was my taking presidency of the Samuel Johnson Society, a vibrant and utterly committed group dedicated to celebrating the work of the most memorable dictionary-maker. The second was editing a new edition of the reference book that, after the Oxford English Dictionary, must be the favourite on my shelf, Ebenezer Cobham Brewer's Dictionary of Phrase and Fable. Both have reminded me of how much we are all, knowingly or unknowingly, in thrall to our language.

The consequence is that I have spent much of my time absorbing such gems as the adjective for "having beautiful buttocks" (callipygous, a Greek term that referred originally to a statue of Aphrodite which was particularly well blessed in that area). I now know that the original job descriptions of a "urinator" and a "fireman" were, respectively, someone who dives under water, and a man of sudden passion. I have found myself becoming like Brewer himself, "a snapper-up of unconsidered trifles" – trifles that are "not too worthless to be worth knowing". Among my finds are the story behind "oaf", derived from the Old English for "elf" because popular legend held a slow-witted child to be an elf's offspring, left in the cradle by fairies who would steal a perfect child and leave the oaf behind; and a captivating definition of "hiccuping" which, in Johnson's 18th century, was "to sob with convulsion of the stomach".

The character of our language defines us, and dictionaries say as much about us as about the way we speak. There is an impressive story that the Holy Roman Emperor Charles V was selective in his choice of language, preferring to speak Spanish to God, German to soldiers, French to diplomats and Italian to women. English, it seems, he used sparingly – allegedly only to converse with geese. Absurd and unflattering such national portraits may be, but it's hard to deny that we are what we say.

What is more, English offers us hundreds of ways to say it. Take the act of gossiping: if the number of terms for it is anything to go by, Charles V may have had a point. In Berkshire and Staffordshire they chopse, while in West Wales they clonc. Lancashire has jaffock; Somerset, hamchammer; Yorkshire, magging; and Norfolk, tick-tatting. If you are the person doing the gossiping, you would be a blatherskite in Durham, a cagmag in Gloucestershire, a caller in Yorkshire, a clat-can in Lancashire, and a yapper in Essex. There are dozens more, and the wonderful and unexpected news is that, as the BBC's Voices survey recently showed, British dialect is alive and well. We may be losing the languages of lost trades and rural pastimes, but all the while the young are taking the words of their parents and grandparents and mixing them up with their own. The result may often be slang, but it is local slang.

As a nation of apparent gossips, we like talking about language, too, particularly those jokes in which foreigners get it wrong. Johnson's dictionary was celebrated as a symbol of British Empire. Sometimes its influence could have dramatic results, as the writer Henry Hitchings has related. In the summer of 1775, the toast of British high society was Omai, a young man brought back from Tahiti by Captain Cook's party. The story has it that, having gathered from Johnson's dictionary that "to pickle" meant "to preserve", Omai saluted Lord Sandwich, Admiral of the Fleet, with the hope that "God Almighty might pickle his Lordship to all eternity".

For its native speakers, too, English lends itself beautifully to jokes. We love Shakespeare for his puns as much as his plots, and English speakers excel at wordplay. It is all around us, in tabloid headlines, adverts, graffiti, on stage and on TV (including Countdown). And, as the linguist David Crystal has pointed out, it is a game with which few sports can compare because we all start on a level playing field. "Language play," he notes, "is a fundamentally egalitarian pastime."

You would be forgiven for thinking that reading an 18th-century dictionary might be less than exciting. Or any dictionary for that matter, although Ammon Shea's Reading the OED: One Man, One Year, 21,730 Pages, proved a surprise hit. On the course of his read he will have traced the winding journeys of such words as "luxurious", which first meant "lecherous", or "buxom", once applied to someone of either sex who was courteous and obliging. Shea would no doubt relish some of Johnson's delightfully succinct definitions such as, for the word "rant", "high sounding language unsupported by dignity of thought", and, for a kiss, a "salute with the lips".

New words fascinate us even more – they are a language's shop window, and show us creating a language fit for the present and then becoming voyeurs to its journeys. When it comes to English, the past is rarely just that – words turn out to be remarkably circular. Take "ground zero", once a term for the site of a nuclear bomb before it was reassigned to the site of the twin towers, or "chav", a 19th-century Romany word for an adult man that was explosively reconfigured in 2004. There is even a Johnson of the Twitter world, Tom Morton, whose takes on modern life brighten my day. Witness his description of last summer's riots in fewer than 140 characters: "The Tottenham Mob does cry for Justice, yet channels its Might unto the Liberation of Training-Shoes from Mr JD Sports", and, on a lighter note "America's Got Talent (n.) Vaudeville Vindication of America's most hopeful Troubadours by England's most ghastly People".

Whatever you think of its current state of health, English never ceases to provoke. Ask any group of people, young or old, for their favourite word or the one they loathe, and the conversation will flow. My current favourite is "halcyon", my most hated "moist". The responses will be all about how we live and where we come from, because a single word can hold as much resonance as a song, perhaps even more. As long as we keep caring, English will push ahead in its merry, mucky and beautiful ways. And we will keep on gossiping about it while it does.

And in case you were wondering what they mean, a Flemish eye is a nautical knot; a knock-knobbler was a Victorian dog-catcher, and a gavelock was once an artificial spur on a fighting cock.