Lisa: If your character has a distinct regional accent is it necessary to write their dialogue 'in accent' or enough to say where they are from?
Good question. A lot of scripts just say where the characters are from, or will state that a certain character has an accent, but not make much of a big deal of it in the dialogue. And that’s okay, that can work, but it is much more enjoyable to see the distinctive dialogue in play. It can give so much more colour and texture to a character (or characters) if they speak with individual voices that are clearly identifiable in the script.
Let’s say one of your main characters is a Geordie lad. Immediately, this gives him a distinct vernacular in which he will express himself. For example, instead of saying: “I’ll do anything for a fiver”, a Geordie bloke will say: “I’ll do ‘owt for a fiver, man”. And if you have this kind of dialogue in the script, then it’s going to give the character and the story some pace and humour, especially if he’s the only Geordie in the flick. If the film’s about a group of Geordies, then they will all speak in their particular dialect but it should be down on paper as much as possible so that the reader gets a sense of authenticity and tone from what they’re saying.
Look at The Wire. Every person’s character is clear and defined, and they all speak with a distinctive voice, using the unique slang and vernacular of the Baltimore streets. The writers must have a blast putting down Omar’s dialogue, or Bunk’s, or Bodie’s or any of the smart-ass street kids. You don’t need a Baltimore ear to follow their words but listening to them speak gives them and their world so much more texture and credibility, not to mention humour. And it’s not just gangsta talk either, some of it is given a neat or elegant turn of phrase, witness this exchange at a tense gun stand-off: “I see you favor a 45.” Omar: "At night I do. And I keeps one in the chamber in case you ponderin'.”
So, in answer to your question: yes, by all means, write in the character’s regional accent or particular turn of phrase. It will add so much more to your script than others who try but give it the usual bland clichés and exchanges.