Some would say it's a combination of tone and style. Yep, OK. But it's deeper than that, I think. It brings in elements of the writer's own voice as well. Some writers deliberately change their voice in each work - others don't worry about it because it becomes part of how readers recognise them. And when you are writing in first person, in particular, how do you separate the narrator's voice from the voice of the writing? Can you?
Our obsession with first person these days both muddies the water and adds to the possibilities of what voice can do. What if you can't change your voice through style and tone? Can you change it via a different kind of narrator?
A novel gives you a lot of time and words to experiment with voice, and a lot of space in which to be inconsistent if you haven't nailed your character well enough. In short fiction and poetry, one story or poem can have a very distinctive voice. It's when you put a lot of them together that problems might arise. The following is a comment from a review of Cate Kennedy's new collection of short stories (Kennedy is well known here in Victoria, if nowhere else, for winning nearly every short story competition, including the Age twice, over a period of 2-3 years):
This is the problem with collections. Placed together, stories can rub together to create chemistry and a cumulative sense of ‘life’, but the risk is that their proximity can reveal shared flaws.
This is from a review by Delia Falconer which you can read at http://home.vicnet.net.au/~abr/Sept06/Falconer%20review.htm
You may be very accomplished at writing short fiction, but when a bunch of stories are read together, what can sometimes happen is a 'sameness' of voice emerges. In poetry, it tends to be a sameness of phrasing, chosen words, similar subject matter rehashed.
What originally led me to think about this was reading 'Just In Case' by Meg Rosoff this week. Like many others, I really liked her first novel 'How I Live Now'. In HILN, the point of view is first person and the story is being told by a narrator looking back. The language is often lovely in its descriptions, and emotion is created with a tight rein that makes it more effective. 'In 'Just In Case', however, Rosoff has apparently decided to change horses and gone for omniscient POV, moving between characters' thoughts and emotions yet always keeping the reader at arm's length. This may well have been a sensible choice, as the main character, Justin, dives into madness and first person POV could have been both smothering and unbelievable. But it left me feeling disgruntled with the book, quite distant from the characters and the story and often tempted to put it down and give up. I'll be interested to read reviews of it, especially after the first book was very positively reviewed by all except those who objected to the narrator having an affair with her first cousin!
A writer friend is currently struggling with the new Barry Maitland crime novel, quoting sentences which are truly awful to read, despite the precise punctuation (Question: how many clauses can a writer fit into one sentence and still make sense? A: depends - if you're Annie Proulx, as many as you like). I, on the other hand, found a Maitland I hadn't read in the library book sale for 50 cents, and thoroughly enjoyed it, up until the last thirty pages. Then the author seemed to suddenly decide he was short of a plot twist or two and piled in two more that seemed rather ludicrous, and then a character who proceeded to do the 'now, dear reader, here is the explanation of how it all happened'. Tsk tsk.