Philip Hensher: How to win the cruel game of paranoid pronunciation

'I suspect the last time "gewgaw" was used in conversation was by Mrs Agnes Porter in 1943'

So I am having dinner with my only A-gay friends, James and Alberto, and James is comprehensively dissing the taste of some mutual acquaintances. We'd all been hearing about the year-long doing-up of the new house of these acquaintances, but James and Alberto are the first to glimpse the full horror of the result, and have an eager audience.

"Matching paintings – you know, sort of Laurence Llewelyn-Bowen abstracts, one green, one red, one yellow. There's a 'cello in the corner."

"A 'cello?"

"A 'cello. Probably came with the books –you know, buy three yards of books, and we'll throw in a 'cello for the artistic effect. Not one nice piece of furniture either – everything gold and heavy from Harrods, a steel kitchen with clever lighting, and every surface covered..." – James takes a swig – "...with gewgaws."

"With?"

"Gewgaws."

James pronounces the word with two hard Gs. I am impressed. "Is that how you pronounce it?"

"I think so – how else would you say it?"

"To be honest, I don't think I've ever heard anyone try to say it. Jew-jaws. Gew-jaws. Jew-gaws. Bijou gewgaws. No idea."

The table breaks up from the rapt contemplation of the sins committed in the name of interior decoration and falls to muttering the odd little word that everyone knows, and no one has ever tried to say.

There's a fascinating area of language between active competence and full ignorance, a body of vocabulary one understands and doesn't use. The active vocabulary of an individual is surprisingly small; even native speakers often get by with a spoken vocabulary in three figures, and beyond that, before we get to "haruspication" and the vast incomprehensible body of English diction known only to the OED and the late Anthony Burgess, there is a vast and fluid body of words that are probably only ever written and read, like medieval Latin. I rather suspect that the last time the word "gewgaw" was used in conversation by an English speaker before last Friday was by a Mrs Agnes Porter, one Tuesday afternoon in 1943.

The fascination of this shadowy volume of words is partly a linguistic one, but partly, also, a social one. Of course, the lifelong development of linguistic competence in an individual mainly proceeds through speech, as a child hears a word and repeats it. But, in an educated person, there is the shakier route of reading a word and attempting to introduce it into his conversation; at which point the vagaries of English spelling start to present a problem. Two common slips, both of which I committed when younger, were pronouncing "misled" to rhyme with "twizzled", and "banal" with "anal".

Names, particularly foreign names, are a gigantic minefield, and anxiety in the area is so strong that I once invented a rather cruel game called Paranoid Pronunciation; the rules were that one would pick an unsuspecting victim and embark on an elaborate conversation about some minor artistic figure, pronouncing his name in so plausibly eccentric a way that one's partner would be driven to imitate it. An extra point was scored if he did this without any acknowledgement. I had great success pronouncing Osbert Sitwell's first name as Orbert, and once effortlessly got an entire committee to talk about Makedonia.

But the other fascination of it, for a writer, is an aesthetic one, particularly when you consider that many items of the unused vocabulary are not in any way elaborate words. Tabloid newspapers are full of words that one has never heard anyone say; "slay", or "storm" used as a verb. For a writer, there is an urgent question about the appropriateness of venturing deep into this territory. Of course, one could not write for long within the limits of an individual's active vocabulary; it would be terribly dull. But it's always apparent when a novelist, writing dialogue, has given no thought to the difference between words a character might know and those he might say.

And there's a looser sense, too, that any good piece of writing ought to be based in the active vocabulary, and venture away from it with care. Once or twice, giving a reading from a novel of mine, I've been tripped up by the sudden appearance of a word that I wrote thoughtlessly, perfectly familiar with its meaning and etymology, but not entirely confident how it was pronounced. I can't help thinking that if writers, from the journalists on The Sun to Nobel-prizewinning poets, were more in the habit of wondering, before they used a word they had only ever seen in print, whether it was entirely necessary, they would write rather better.

The temptations of elegance are substantial, however. Journalists will go on writing "slay" when they mean "kill"; poets will go on writing "yet" when they mean "but". One doesn't always want to be plain; it is important to draw on a richer vocabulary than the pub conversation. I've already used half a dozen quite ordinary words in this article that I would probably never use in ordinary speech – vagaries, venturing, shadowy and so on. But it's important to feel when you're leaving the language of speech, and to write "yet" with the same deliberation you'd use before writing "interlocutor".

It's pronounced "jew-gaw", incidentally. I must try it some time.