In poetry, the words on the page are all you have, and if you are doing your job right, all you need. Diction, a fancy word choice for "word choice", refers to the art and science of choosing the most lively, euphonous and surprsing word to convey your meaning. If you've workshopped much, and I hope you have, you have had the experience of someone quibbling with a single word in your poem, long running debates over whether "going" or "running" is the best word. While this can be frustrating, a single infelicitous word can spoil a reader on a poem. In this essay we will talk about broad categories of "poetic" language and the principles you can use to choose the right word for a particular spot.
First off, though, let us deal with what most commonly comes to mind when someone says "poetic language", and discuss why it's perhaps not the best in this day and age. Here's an excerpt from Walt Whitman's "As I Walk These Broad Majestic Days":
As I walk these broad majestic days of peace,
(For the war, the struggle of blood finish'd, wherein, O terrific Ideal,
Against vast odds erewhile having gloriously won,
Now thou stridest on, yet perhaps in time toward denser wars,
Perhaps to engage in time in still more dreadful contests, dangers,
Longer campaigns and crises, labors beyond all others,)
Around me I hear that eclat of the world, politics, produce,
The announcements of recognized things, science,
The approved growth of cities and the spread of inventions.
Beautiful and stirring, but when was the last time you said " O" anything? What about other Romantic staples like " Alas!"? Or "Alackaday!"? "Thou art"?? Obviously, the accepted poetic diction has changed radically over time- whereas Shakespeare and Keats were expected to talk like that, if you, in the 21st century, come out with some thees and thous you will be ridiculed. So love Romantic poetry all ya want, imitate its sentiment, but don't slavishly copy its langauge, however hard that might be. Our first principle:
Use the language of your time and place. This is not to say you can't have a wide vocabulary and sound educated- you should, in fact, but sound like an educated person of this century. Most importantly, poetry thrives on new and fresh and surprising language, and what could be more fresh than the talk of today? Of course you still adhere to the principles of sonics laid down by my colleage, but you explore those sounds in your own speech, not that of the 19th century Lake District.
Which leads to an observation I'm sure you'll make on your own after reading much of the English poetry of past centuries: every age thinks the diction of the last flabby, overblown and pretentious, and its own concrete, vivid and unpretentious. Tastes change, and mastering effective diction is partly a matter of being on top of the times. The Modernists flushed much of the above described language, and favored the mundane, the trivial, even the nasty. They expanded the range of possible topics: alienation, urban malaise, senseless death and destruction, sex, more sex, etc. Alackaday, indeed. These new subjects required new words and especially less rhetoric, or the use of elaborate tone and grammatical constructions/ inversions, i.e : "For the war, the struggle of blood finish'd, wherein, O terrific Ideal ". Out with that, and in with
There died a myriad,
And of the best, among them,
For an old bitch gone in the teeth,
For a botched civilization,
Charm, smiling at the good mouth,
Quick eyes gone under earth's lid,
For two gross of broken statues,
For a few thousand battered books.
(from "Hugh Selwyn Mauberly", by Ezra Pound)
What feelings do words and phrases and like "old bitch gone in the teeth", "botched", and "two gross of broken statues" create? What feelings about war does such diction imply? How would you describe Pound's grammar? The answers to those questions will give you an understanding of the sea change in diction that occurred in the early 20th century, and why we can never again say " Against vast odds erewhile having gloriously won".
Keep your word choice honest and your grammar simple.
Before we go on, let me dispel the notion that I am saying flowery words/grammar or familiar words are never appropriate. To quote an old guy, Samuel Johnson, "Words too familiar, or too remote, defeat the purpose of a poet". That is, writing pure teen slang just because it's new is no better than sounding like Keats. Of necessity, most of the words you use would have been understandable to Shakespeare (who was a rabid word-inventor), but adapting the tone and vocabulary of your day to poetry rejuvenates both poetry and the language.
Now for some linguistics: You will often hear English words classified by their ancestor language or language group, and different poetic properties assigned to each. The distinction is made between Anglo-Saxon words and Latinate words. These are far from being the only sources of English (especially American English), but they are dominant for our purposes ( a short history of the English language: http://www.cryptograph.com/englang.htm
Anglo-Saxon words are the most common, and include useful workhorses like prepositions, conjunctions, pronouns, and demonstratives, but also many concete nouns and verbs. Imagine no-nonsense Germanic warriors sacking Rome. Short, sharp words like grunts or thrusts. All cuss words
When you want imagery and action, go Anglo-Saxon! Anglo-Saxon words: nouns, verbs, etc, should make up the bulk of your poems as they keep your poem sensual and vivid, and trust me, folks, that's what you want
Latinate words are just what they sound like, words derived from Latin or its daughter languages. Latinate words tend to be "high vocabulary", formal, multi-syllabic, composed of identifiable Greek/Latin roots, words for persuasion, rhetoric, euphemism, nice subtlties and abstract concepts. Imagine the debate in the Roman senate about what to do about the barbarians. Long, flowery words. Compare herds of cows to cohorts of bovines.
Go latinate when you want to obfuscate! That's not always a bad thing: a latinate word at the right time can heighten the mystery and ambivalence of your poem:
Bind us in time, O Seasons clear, and awe.
O minstrel galleons of Carib fire,
Bequeath us to no earthly shore until
Is answered in the vortex of our grave
The seal's wide spindrift gaze toward paradise.
(from Hart Crane's "Voyages II")
"Vortex" and "paradise" are both oringinally from Latin, and serve to take the poem beyond the physical.
More generally, you want words that get up and move, that snap and crackle, that hit you when you weren't looking. Pick the more interesting, vivid word from each of the following pairs of synosyms:
Of course, overuse of the words in the second column can make a poem too hectic, and they aren't always appropriate to the meaning. But ask yourself with every word you choose if there is not one that is more active and exciting.
Action, detail, color.
In summary, what can we say about good poetic word choice? It is modern, fresh, as simply worded as possible, primarily Anglo-Saxon, and tries to make the text have a pulse.