Diction is one of the most important hallmarks of a writer. It is how he leaves his mark on his work, distinguishing it from the works of others.
"The difference between the almost-right word and the right word is really a large matter."
Diction is represented by the choice of words made by the writer. While the theme, the plot, and the construction of a novel can be common between two writers, it is the choice of words that separates one from the other. This refers to the connotation of the words in the context of the topic, rather than the meaning.
Apparent synonyms may convey completely different connotations if used in different contexts or around different words. For instance, the words 'slay', 'kill', 'murder', and 'assassinate' all refer to the act of killing a human being. However, depending on the context, the words may convey completely different emotions about the same act. A rebel taking the life of an oppressive ruler would be considered an 'assassination' by the rebels, a 'killing' by the officials, and a 'murder' by the law.
Similarly, a character depicted to be uttering "y'all" instead of "you all" can conjure up images of rebellion, of youth, or can even highlight racial undertones.
It is this choice of words that set the tone of an author's writing. This tone set by the peculiar application of vocabulary is called diction.
There are numerous types of diction, all of which can be employed to convey a particular setting or background. Here's more information on the various types of diction, and their examples.
Concrete diction is depicting a scene in precise terms so that the reader has no scope to sway from the picture you want to build. Descriptions of physical places or objects can be given through concrete diction so that there is no discrepancy between the place in which the author intends the story to happen, and the place in which the reader imagines it. It enhances the experience of the reader by forcing him to participate in the author's vision, rather than allowing him to wander off by modifying the scene with his own imagination.
For instance, consider the famous quote at the beginning of J. R. R. Tolkien's The Hobbit:
In a hole in the ground there lived a hobbit. Not a nasty, dirty, wet hole, filled with the ends of worms and an oozy smell, nor yet a dry, bare, sandy hole with nothing in it to sit down on or to eat: it was a hobbit-hole, and that means comfort.
Tolkien could have simply written something on the lines of "it was a comfortable hole". But by describing the negations of the conditions in the hole, he paints a clear picture of the actual conditions in the hole: If not dirty, it must be clean; if not filled with an oozy smell, it must be filled with fresh and pleasant smells; if not bare, it must have comfortable furniture. The words 'bare' and 'sandy', in particular, bring to mind a desert―lifeless and barren. So if the hobbit-hole is not like a desert, it must be like a lush oasis.
In direct contrast to the above, abstract diction allows the viewer to imagine his own version of the scene depicted by the author. Often, this is used to convey emotions. However hard the author may try, he can't make the reader feel the same emotion as his characters, since the readers' emotions are based on their own experiences and memories.
While describing emotions is an inevitable part of abstract diction, there is also one that deals with the example given above. In the aforementioned Tolkien quote, simply stating that the hole was comfortable and tidy would have carried the same meaning as the long-drawn description. However, in that case, readers couldn't have seen Bilbo Baggins' hobbit-hole, they could only have seen their interpretation of Bilbo's hobbit-hole. Such descriptions, which allow the reader to infuse their own imagination into the author's vision, are considered a mark of weak writing.
Often, a writer wishing to portray a conversation as happening in the common tongue, uses words that may not be classically accurate, but are used by the masses. This usually refers to particular geographical locations or other social identities. Local accents can be used to indicate the geographical location of the speaker, or particular peculiarities of the language can be used to indicate the allegiance to a particular social group of the speaker. There are many such examples of colloquialism in literature.
One of the most famous and exalted examples of colloquialism is J. D. Salinger's novel The Catcher in the Rye. Narrated from the point of view of a rebellious teenager, it employs various phrases commonly used by teenagers. This also includes some offensive language, but it serves to enhance the setting of the novel, by making the narration more authentic. However, illustrating the thin line between colloquialism and slang, the language in this novel can also be considered slang, since only individuals of a certain age and social background talk like that.
Another popular example is the novel and movie Trainspotting, by Irvine Welsh and Danny Boyle, respectively. While the novel used Scottish slang to highlight the location of the story (Edinburgh), the casting of Scottish actors such as Ewan McGregor in the film gave it even more credence.
Mark Twain's The Adventures of Huckleberry Finn is one of the pioneering works employing colloquial diction. It set the setting for the period depicted in the film, and also showed the public that books could be written in such an informal manner.
Closely related to colloquialism, slang is often used as a substitute for the former, but there are a few differences between the two. There is no comprehensive, universal definition of 'slang', but it is considered to be a group of words in a language that are not generally used. It has a slight negative connotation to it, as slang is often considered uncouth. This is where the subtle difference between colloquialisms and slang lies.
However, certain words being considered slang is highly dependent on the period, since many slang words get accepted into the mainstream lexicon over time. The words 'gig', 'foxy', and 'spurious' are examples of words that became more accepted by the majority, having originated as slang. Colloquialisms that haven't spread far enough can be termed as slang.
A well-known example of slang is seen in the movie Airplane!, which parodies the suspicious attitude of Americans towards those speaking in a different tongue, by providing 'normal' subtitles for the Jive slang spoken by two African-American passengers.
The phrase 'my bad' is a commonly used slang term. Grammatically, it is a null phrase, but it is understood by the majority. Its widespread use means that this can also be an example of colloquialism, showing the thin boundary between the two.
Trainspotting can also be considered as an example of slang. It uses various terms used exclusively by the heroin-using community to refer to various drug-related activities. The words mean different (perhaps more respectable) things according to their normal usage, but they denote a different connotation when used in the context of the heroin trade. Confusingly, the exclusive relation of some of the words to the heroin trade means that they can also be considered as jargon of the heroin trade.
Jargon is a lexicon of words related to and spoken by practitioners of a particular trade or field of knowledge. Like slang, jargon develops or is deliberately developed as a way to allow the practitioners of a field to share ideas in words that can't have disparate meanings or connotations, free of the vagaries of the colloquial.
For instance, the binomial nomenclature in taxonomy can be considered a scientific jargon, since the same animal is known by different common names in different languages, but it has a universal name that is not dependent on the native language of the speaker. Tigers may be called baagh in Hindi, tigre in Spanish, and teigr in Welsh, but experts speaking each of those languages can refer to it as Panthera tigris.
Some binomial names eventually spread enough to become the common name of the organism in question. An example of this is Aloe vera, which is known as aloe vera in non-scientific circles as well. Other examples include computer jargon such as 'bit' and 'byte', which is now commonly understood all over the world.
TV shows about the legal system or crime often use official crime investigation or legal jargon. The crime series Bones is notable for regularly using scientific jargon and then having a 'lab-coat' character explain it to the unknowing FBI agent, also explaining it to the viewer in the process. The crime drama series Breaking Bad also uses considerable amounts of chemistry and methamphetamine jargon. The Bond movie Casino Royale includes a significant amount of poker jargon, such as 'bluff', 'full house', and 'straight flush'; the nuances of the plot would be lost on those who don't know poker terminology.
These are the most important types of diction commonly observed in literature.
The importance of diction in literature is such that some experts claim that one should only write with nouns and verbs, excluding the adverbs altogether. Writers like Ernest Hemingway, the brain behind the 'Iceberg Theory', used this skill to great effect. Hemingway 'showed' the 10% of the literary 'iceberg' to the readers, while 'telling' the 90% hidden underneath through the connotation of the apposite words. This style forces an author to seek just what he needs, and discard what doesn't fit, by however small a margin.