Ey up, just want t'say few words about dialect in t'writing. No, that's not some monster outta Doctor Who. That there's Dalek. Dialect is speaking, like, only like normal folk do it, like.

There's no doubt that dialogue is one of the key elements to master as a writer. It can be one of the most difficult; it's frequently one of the most overlooked, but it can also be one of the most enjoyable. When characters speak they don't just share information with the reader, they provide a degree of understanding of themselves as characters. Get their voice wrong and you break the illusion. Get it right and you add to the pleasure of getting to know them for the reader as well as yourself. As a comedy writer, of course, it's easy to consider such characterisation as important, but for the serious writer too there are things to consider.

Firstly, it's about what your characters say. I recently read a book in which a key character was continually described as being enigmatic. The word appeared almost every time he did, like a lingering bad smell. The overuse of the word bugged me a bit (these things do when you're a writer), but not quite so much as the fact that the character spent most of his dialogue expositing. Now, correct me if I'm wrong, but a defining feature of enigmatic people is that they tend not to tell you much. An enigmatic character would be a character of few words - secretive, shady.

But you can see how the mistake was made: the central character of the book was, as is so often the case, a newcomer to the world. The world itself had complex elements that needed to be understood, as well as a back-story to be revealed, and the enigma was the only character on the inside in which the author had a great deal invested. The job, therefore, fell to him. The author could have created another character to serve as a guide, or even allowed the central character to find things out for himself, but they should have used the enigma only occasionally and, rather than referring to him as enigmatic, made his words (or lack of them) speak for themselves. Being fond of one of your creations is fine, but there are inherent dangers in overusing characters who are defined by a limited range of characteristics. Ford Prefect's malformed public duty gland would be hard to sustain if you made him the central character in a Hitch-hiker's book. Jeeves would be a lot less the deus ex machina if he were more the focus than Wooster.

Expositing is one of the more common problems which authors face in dialogue. There's always a certain amount of information to get across to the reader. If the central character is an insider you can do a certain amount of this in their internal narrative, but when the character is an outsider, or when there are people in the world who have key parts of information which need to be discovered rather than known by the central character, dialogue is often the easiest way to get them out there. The trouble is it can feel a bit clunky when one of your characters effectively makes a speech to tell the reader what they need to know. Most of the time it's not how people speak.

'That's Perkins,' said the barrister. 'He's been up in front of the judge fifteen times over the last ten years, every time for a minor offence. Four shoplifting cases, five petty thefts, three assaults, an aggravated burglary and now murder. He had a troubled childhood - father died when he was three - and he lived with a dominating mother and three sisters. All the standard ingredients for a case like this.'

'And do you know his inside leg measurement?'

Jeffrey Archer does this all the time.

Probably the worst genre for expositing is science-fiction. A book set in our world can assume the reader understands a certain amount of what's going on - you don't need to explain the concept of the staircase, for example - but in science-fiction, the ascendotron might not be so obvious. Unfortunately, if the characters are all of the world in question, this presents a problem: in the same way you wouldn't expect characters in a regular book to discuss the nature of the chair or the water cooler, it cannot be right for sci-fi characters to discuss the furniture of their world as if it were a novelty - unless it's important to the plot that it is a novelty, of course. Having an outsider or having inventions as new or unusual would get you out of some fixes, but you can't do that every time. This is particularly true in a series: Perkins the off-worlder can be expected to not understand a few of the novelties of the big planet on his first visit, but three years in when he asks for an explanation of the pschyo-phone it won't just be the other characters who think he's stupid.

You could make your life easier by limiting the differences between your world and ours, but sci-fi wouldn't be sci-fi if it was just a room with a view of a quantum phasomatic. You want your world to feel different and that means gadgets, slang, entire ways of life will be different. Some of this will need to be explained to the reader. If you're writing for radio that either means a narrator or dialogue where characters are introduced to the niceties of life (unless they're obvious in context), but for a novel you can reserve the explanations for narrative passages. That's not to say nothing should appear in dialogue, but if Perkins should already know about it, don't tell him.

Once you've established what your characters should say, you need to consider how they should say it. It's no good describing your character as a rough diamond if he talks like a newsreader. Similarly, a character who is set up to be hesitant or nervous is hardly going to speak in long, coherent sentences. If Perkins is a serial criminal you have to ask yourself if he is a Moriaty or a thug. A Moriaty would speak in faux-intellectual over-dramatic stylised tones (aha, Mr Barnes, but how do you know my cane is not actually tipped with a rare snake venom?) where the thug would be blunt and to the point (you try it with me, Barnes and I'll stick ya). Both, however, would disregard the strict rules of English the writer strives to apply to narrative (albeit with varying regularity). Even posh people don't always talk proper.

So far, of course, all of this has applied to how the individual character speaks. The art of conversation, in art as much as life, also depends on knowing when not to speak. Whilst having Perkins explain his scheme for world domination in a single uninterrupted soliloquy might be very efficient use of time, in practice his henchmen are bound to need explanations, clarifications - or simply to ask to be excused to go to the toilet. His henchmen don't, after all, have his intelligence. Although they may have his bladder control. Real conversation has a bit of back and forth, and whilst there are occasions when a character should be seen to lecture, most of the time it just comes across as amateur.

Continuous monologue also robs a writer of a key tool in establishing a character - their physicality. How a character moves, their facial ticks and involuntary physical reactions can open a window on the soul in a way which they would never deliberately reveal in words. If Perkins steeples his hands in anticipation of something particularly devilish, raises an eyebrow when being sly or bangs the table when feeling aggrieved these are all things which add to his characterisation. Someone who simply talks uninterrupted might as well be a ventriloquist's dummy for all the personality they exhibit (and gat's gen I conquer the girld).

Finally, we return to where we came in - dialect. As a writer I pay a great deal of attention to the way people around me speak. Whether it's the slang and the malaprops which an individual consciously adopts to mark themselves out, or the subtle linguistic traces which come from a regional or non-English upbringing, it's all grist to my mill and ink to my pen. For a comedy writer, there's a certain joy in exaggerating these nuances, but even for the serious writer there can be a great deal to gain by giving thought to the subtle tics of a character's speech. Sometimes it helps to enrich the role of a minor character, sometimes it allows you to dispense with dialogue tags or background information, but mostly it helps to reinforce the breadth of your world. Would Die Hard have been a better movie if Gruber was played as an Englishman rather than simply by an Englishman? Of course not. Could Scott have written Rob Roy with a cast seemingly from the Home Counties? Hardly. And likewise if Perkins had the slightly staccato delivery of a white South African or the awkward conjugations of an English-speaking Russian it might add a layer to his performance that implied a background the writer needn't then fill in.

Sometimes I cut an odd figure when I'm writing. I'll type for a bit, then I'll sit back from the keyboard, gesturing and reciting, getting under the skin of a character in a manner reminiscent of a character actor. Because that's what writing is - a performance: a poor script might be improved by the introduction of suitable actors to bring their talents to the roles, but a poor novel has only the reader to interpret it. It therefore falls to the writer to elevate the performance of their characters, to bring life to creatures who exist only in ink and paper and imagination. Dialogue is a key part of this performance and one an author overlooks at his peril.