It is lunchtime in The Horseshoe Bar in Drury Street. Several tall lights on tripods have been focused on one of the wooden tables. A man sits at the table with his back to the door. A television camera has been set up. It is trained on the door into the bar.

My moment has come. For I will be entering through that door. The camera will catch me as I enter, follow me to the bar, where I will order a drink, and doggedly pursue me as I sit down at the table opposite the man with his back to the camera. The interview will begin. It is for a film about Glasgow to be shown in West Germany.

I stand outside, waiting for the shouted signal. It's just like being in the pictures, isn't it? This is really a kind of acting, isn't it? I hope the rain doesn't plaster my hair to my head the way it usually does, making it look like a greasy balaclava. 'Okay!' Camera, action, shoot.

I enter. I walk over to the bar in a manner I hope is casual and ask for a whisky. The manager, who has obviously given us permission to invade his bar in the first place, smiles and hands me a huge whisky which he has had sitting ready under the counter. My quest for method-school naturalness, an inhabiting of the part, is thrown by this. Why not use the optic? I have reached into my pocket and pulled out some money but the manager smiles again and turns away, commendably refusing to hog the camera. But what do I do with the money? Donate it to charity? I put it back in my pocket.

By this time, as I stumble towards the table, I feel the omens are not propitious for an interview in which I'm supposed to try to give a real sense of Glasgow. We've already, in about 20 seconds, managed to depict Glasgow as a city where casual strangers entering a bar are given bowls of free whisky. I envisage legions of outraged German tourists picketing Glaswegian pubs. I sit down and nod to my interviewer, who smiles reassuringly back. Even this part, now that I'm doing it, feels daft to me. Won't it convey the impression that people meeting for the first time in Glasgow bars conduct interviews with each other? But it's not my programme.

`Tell me,' my interviewer says, 'what, do you think, is the special quality Glasgow bars like this have? What's typical of them?'

This is probably my chance to explain that what has just happened isn't typical and that, for example, you usually have to pay for the drink. But the remorseless eye of the camera is on us and I chicken out. Instead, I go into a spiel about the communal nature of at least some Glasgow pubs, the likelihood of being engaged in conversation, of having your privacy benignly invaded, of being interrupted — at which exact point I'm aware of a shadow across our table and the lighting man dancing like a dervish in the background and I hear a voice saying: `Oh-ho, whit's gaun on here, then?'

A fairly elderly man has joined us at the table and is interviewing the interviewer. The interviewer is English and there seems to be some language difficulty. Offering my services, I ask the man what the problem is.

'Oh, no problem, son,' he says, his eyes assessing what size of coffin I'll require. `Ah jist want tae know whit's gaun on here.'

We continue talking and, while he studies the lights and checks out the television crew, I explain that we're conducting an interview.

`Interview?' He holds up a stiff, leather-gloved hand that is obviously made of something other than flesh. 'Interview? Ah'll gie ye an interview. How about interviewin' the war-wounded?'

The man said more, much more. I've never seen the finished film but I understand the director intended to cut that moment of interruption. Certainly, the cameraman stopped filming very quickly, which was a pity. The scene was Glasgow in action, far more eloquent than any conversation we could have had.

The man wasn't just the incarnation of the point I had been trying to make. He was an interesting user of Glasgow speech, that aspect of the city in which I see most hope for the survival of its identity undiluted. For Glasgow's soul is in its mouth. Anyone who wants a quick and painless introduction to the essential Glasgow should read Michael Munro's excellent dictionary of Glasgow speech, The Patter, full of superbly creative examples.

Even a cursory acquaintance with that speech will reveal that it is not merely a collection of slightly different words. It is the expression of a coherent attitude to life, a series of verbal stances as ritualised as one of the martial arts. But it is also continuingly inventive, an established style within which individual creativity can flourish.

The salient features of that style emerged directly from the hardness of life In the streets of a major industrial city. Such a life demands the frequent application of painkillers and so there are many ways in which you can be drunk. You can be wellied, plootered, steamboats or blootered, among others. Drunkenness can lead to insults and the designation of someone as a bawheid, a doughheid, a chanty-wrastler, a heid-banger or a bampot whose patter's mince. Insults beget violence and you may find yourself banjoed or burst or rattled or melted or invited to come ahead.

But, in fact, many Glaswegian insults and threats are as much a way of containing violence as of causing it. They are like the warning signals animals emit. Perhaps part of the reason for Glasgow's reputation for being a threatening city is that much of the violence has been codified into speech that is highly skilled in drawing demarcation lines of behaviour. These can make certain conversations a complex map of grid-lines and markings the wise cartographer can interpret: 'No Go Area', 'Dead End', 'Bears Crossing'.

But these are the outer edges of the significance of Glaswegian speech. The core of its style is two main qualities: deflation of pomposity and humour. It's hard to be pompous when you have a geggie for a mouth and a bahookie for a posterior. The humour takes many forms but I believe that the commonest of these is the humour of disgruntlement — that central source of laughter to which we have been led by such diverse practitioners as Evelyn Waugh, Groucho Marx and Woody Allen. So much of Glasgow humour is disbelief under anaesthetic. It is anger with the fuse snuffed but still smoking.

Glasgow speech, like so much of Glasgow itself, expresses partly incredulity at what life offers, partly a way to make the best of things, partly an invitation to seize the moment and to hell with the formalities.

(To read the next post in this series click here.)