Tell it to mi duck, love

Linguistic variations are a great pleasure. Just do some tab hanging in Derbyshire and you'll see

Official definitions are slippery fish, of course, but Wikipedia describes an isogloss as "the geographical boundary of a certain linguistic feature, such as the pronunciation of a vowel, the meaning of a word, or use of some syntactic feature". I'm a huge fan of the unsung and rarely celebrated isogloss, although I prefer to call it the house/arse interface. It meddles with our daily lives all the time in an entertaining and rewarding fashion, reminding us of the diversity of our humanity in the same way that how we eat a bag of crisps does. (Fingers all the way into the salty cave? Tipping upwards as though drinking mead? Handfuls or a single unit? It's a discussion for another day.)

In Barnsley I call my house my house, but if I went to visit my cousins Ronald and Harry in north Derbyshire, they would meet me at the gate and invite me into their freshly wallpapered arse. If I walked down their street and hung the tab, as they say in those parts, I would hear statements such as "I've just had double glazing fitted in my arse", or "My mother's got a detached arse". And they would be said without any kind of music-hall, spinning bow tie, boom-boom inflection in the voice, because it's just the way people speak round there.

Somewhere between Barnsley and, say, Duckmanton or Clowne, an isogloss happens. There must be an invisible barrier just south of Sheffield where the house becomes the arse. If I measured the language of the speakers I passed with an isoglossotron it would record house/hearse/harse/arse and there would be a line I could draw on the road, perhaps somewhere on the south side of Beighton, with a piece of chalk that I happened to have in my house pocket. Or perhaps the isogloss barrier isn't invisible, but only visible in certain lights, like eclipse-glow or bonfire-gleam. That's more intriguing.

Walking to Derbyshire, though, I would have brushed against a number of isoglosses that would have tickled my face like cobwebs in an abandoned building. I could have left Barnsley saying "Now then" to the other Barnsley denizens I met on the way, and they would have "Now thenned" me back. I would have gone through the village of Birdwell and begun to walk down the A61 towards Sheffield and by the time I passed the Kop end at Hillsborough I would have been saying "Nar Den" to the Sheffielders I met on the way.

Somewhere between Birdwell and, say, Grenoside, "th" hardens to a "d". As I passed Wadsley Bridge (where I once saw two middle aged men in suits having a fight, swinging at each other and then dropping the change out of their pockets and bending down to pick it up before resuming the bout) my vowels would have widened slightly, like a clam opening. I would be saying something like "Knorr den", with a hidden "a" lurking somewhere behind the "o" like a first draft. From "Now then" to "Knorr den" over a few miles of post-industrial England; it's hardly Daniel Defoe's A Tour Through the Whole Island of Great Britain, or maybe it is, in miniature.

In Barnsley I would have called everybody, of whatever sex, "love", because living in Barnsley is like being in the rehearsal room of a provincial theatre, without the cravats. When I got within reach of Harry and Ronald I would have been calling everybody "duck".

If I carried on further south I would add a "mi" to the beak end of the duck, so that I called people "Mi duck". My progress southwards, if it was erratic enough, would see me being called a mate, a pal, a butty, a butt, a la' and a lover, as I burst through ranks of isoglosses as if I was bursting through paper walls.

In the end the isogloss hunter-gatherer like me becomes a character in a Robert Ludlum thriller. As well as the house/arse interface, it's the love/duck conundrum, the breadcake/teacake mystery (with its sequel, the bap/cob conspiracy), the pumps/daps question.

So let's celebrate the isogloss, Guardian readers. Some people, perhaps the same ones who think that childrens' playground games have died, suggest that the isogloss is extinct. Prove 'em wrong. Let's gather up these linguistic variations like those scrappers in suits gathered up their change and collect them in scrapbooks until we've got so many that we need an extension built on our arse.