The old folklorists' saw about ballads is that the word derives from the same root as the Spanish "bailar," to dance, and that ballads were originally composed and/or sung in the process of dancing.

The standard example is "Maid Freed From the Gallows," which adds incrementally to a simple story in such a way that, while dancing, you could actually toss in a verse to advance the plot.

Father have you brought me silver ...

I have not brought you silver ...

Mother have you brought me silver ... etc.

This doesn't really apply to very many ballads, though Faeroe Island ballads are often cited to make the case.

I personally think that a traditional ballad is more often than not

1   a narrative using
2   four-line verses, or else two-line verses with refrains like "The broom blooms bonny and so it is fair / I'll never gang doon tae the broom nae mair" on
3   folk themes, whatever those are (i.e., a ballad about "Star Trek" probably wouldn't make the cut)
4   with relatively unsophisticated words, lacking in self-consciousness, and a relatively simple tune (i.e. Sir Walter Scott, though he tried, really never could quite write one, and the tune of "Hello Dolly" really wouldn't fit)

but you'll get a thousand arguments against every word of all four points from ballad singers with different ideas.

Then there's the ballad used as a literary form by Stephen Vincent Benet, Alfred Noyes, and others. Coleridge's "Rhyme of the Ancient Mariner" is a pretty successful ballad imitation, though of course its language is heightened. Literary ballads are fixed in form, and ordinarily have no melodies, whereas traditional ballads tend to vary in text and tune with the singer, which is what is meant by their having traveled and changed in the traditional process.

Many traditional ballad enthusiasts would like to eliminate at least some broadside ballads on one ground or another (as, for example, did Francis J. Child (mostly) in his standard work "English and Scottish Popular Ballads" -- because they never entered tradition, died in a week, were lousy poetry, obviously the work of Fleet Street-type hacks, or whatever. But these productions, more or less the equivalent of newspaper articles on current events and features on past events, come well within the definition of ballads for the most part.

An interesting light on the question of ballad composition/improvisation is the work of Parry and Lord, reported in the book "Singer of Tales," concerning Yugoslav cafe singers who improvise ballads that may last half an hour or more, based on folktale themes, using standard elements to recompose a song that is different every time, depending on audience tolerance and the singer's whim of the moment. This is used to draw parallels to the saga- and lay-style ballads of Scandinavia and France, respectively, and ultimately to the epic ballads sung by ancient Greek balladeers that are believed, by some, to have underpinned Homer's Iliad and Odyssey.

It's sometimes noted that ballads were the TV of their time: satisfying the hunger for music and narrative, just as TV now provides its "American Idols" and its sitcoms and cop dramas. Ugh, but probably true. We're glutted now with entertainers and entertainment, so relatively few people have room in their lives for ballads. Too bad for them.

Whole books have been written on what is or isn't a traditional ballad, including the delightful Evelyn K. Wells oldie "The Ballad Tree." But you'll find the definition of a ballad slithers around quite a lot, depending on whose ox is being gored.

Bob