Several reasons, some merely historical
- Sound is considered an important component of language and hence of poetry. To some it has a visceral effect. So it's natural to exploit patterns of sound and their interaction with meaning.
- Much poetry works by expectation/surprise or tension/release - in the plot, but also in the form. A regular form offers more chances to surprise the reader
- Sound-patterned verse is easier to remember
- Sound-patterned verse is easier to set to music
- The use of a form is an allusion to earlier uses of the form. Writers can expressively follow (or react against) the tradition
- Sounds are a structuring device that can relate distant words or hold semantically unrelated words close together
- Forms provide a technical challenge for the poet
- Readers like a mix of familiarity and novelty. Using forms one can give readers their dose of familiarity without having to compromise the content.
On the minus side, some say that forms are
- artificial, interfering with the natural expression of emotion
- intellectually elitist
- conservative, supporting the social status-quo
Apologists for forms say that
- maybe iambics (even the sonnet) naturally evolve from features of human language - see Paul Lake's The Shape of Poetry. And some they that if the poet doesn't explicitly choose a form, language will impose one anyway
- Wordsworth claimed that Forms were democratic - it's more egalitarian for poems to use a recognised form than to use a private, self-indulgent format. Besides, popular songs use forms
- The assertion that forms are stylisticaly/socially conformist is overdue for
- Some avant-garde movements (e.g. OuLiPo) have used Forms as a vehicle. Novelty of style/content can easily be accomodated within Forms
- Social rebellion has often used forms (UK feminists, etc)
- Use of a Form needn't reflect a naive nostalgia for unity, or a blindness to idealogical forces that can shape forms. Indeed, use of Forms is an indication that language isn't "natural" and "transparent".
Types of Form
Hundreds! They can be classified as
- Visual - forms that can only be seen on the page (Lewis Carroll, Herbert, Charlie Fordham, etc)
- Numeric - forms that require counting: just listening or looking at the page isn't enough - western haiku, syllabics
- Sonic - sonnets, etc
- Procedural - Acrostics, OuLiPo, Harry's DNA piece
Also there are conceptual forms (haiku, for example) and borrowed forms (fugue, quartet, collage).
Alan Reynolds has sorted his poems by form and has written about them. See formally yours
Use of Forms
There are risks associated with using Forms. Nowadays it may be necessary to explicitly point out the Form to readers, even if you don't use Obscure Forms. Also some magazines (especially in the USA) have a bias against forms, though imported forms seem more acceptable. And badly written formal verse can be identified faster than bad free-form can.
Sonic forms seem to be accepted as more natural and less easily missed than the alternatives. Other forms can pose problems that readers can't solve - see Some Experiments in Form.
The Future of Forms
In the USA Forms died out for a while. A decade or so ago an attempt was made to revive them, but that movement's petered out. It's not uncommon for a yearly anthology of Best US poetry to have no formal pieces. In the UK modernism never really took hold. The Forward anthology of 2004 has about 10 formal poems compared with about 30 free-form pieces and 17 pieces that have boxed-shaped, equally-sized stanzas - see The Legacy of Form
- "The Making of a Poem, A Norton Anthology of Poetic Forms", Eavan Boland and Mark Strand, WW Norton, New York/London, 2000.
- "Modernist Form", J. S. Childs, Associated University Presses, 1986.
- "Poetic Meter and Poetic Form", Paul Fussell, McGraw-Hill, 1979
- "Sound and Form in Modern Poetry", Harvey Gross, Univ of Michigan Press, 1964
- "Rhyme's Reason", John Hollander,Yale University Press, 1999
- "The Sound Shape of Language", Jakobson and Waugh, Mouton De Gruyter, 1979
- "The Noise Made by Poems", Peter Levi, Anvil, 1977
- "Hypnotic Poetry: A Study of Trance-Inducing Technique in Certain Poems and its Literary Significance", D.Snyder, 1930
- "Missing Measures", Timothy Steele, University of Arkansas Press, 1990
- "What Makes Sound Patterns Expressive?", Reuven Tsur, Duke Univ Press, 1992
- "The Book of Forms", Lewis Turco, University Press of New England, 2000
- "Patterns of Poetry: An Encyclopedia of Forms", Miller Williams, Louisiana State University Press, 1986