Let’s take a look at a sentence that includes two different ways of joining words together. We rightly think of conjunctions as the part of speech that combines words, but how often we use them, or whether we use them at all, contributes to the design and effect of a sentence. Here is a grammatically simple sentence that is describing the character of an old friend:
He loved the outdoors—and indoors too: old books and fine wine and good friends, conversation, festivity, laughter.
The sentence unfolds neatly into two halves at the midway point marked by the colon. One of the important uses of the colon is to enumerate or exemplify or expand the meaning of what precedes it, and here the word indoors needs some explaining, because it is less common to say one loves the indoors than one loves the outdoors, the familiar natural world and open air. The six things named after the colon are what constituted the indoors for this friend, and it is the manner in which they are presented that concerns us here.
The writer had at least three choices in designing this half of the sentence. The most regular and expected arrangement would have been simply to list the six items, inserting the conjunction and before the last noun: old books, fine wine, good friends, conversation, festivity, and laughter. There is no mistake to correct here, but the statement seems to fall flat, taking on the effect of an itemized inventory, a tone that works against the inherent warmth of the ideas otherwise coldly listed.
Another choice would have been to insert the conjunction and between each and every noun: old books and fine wine and good friends and conversation and festivity and laughter, deleting even the comma so as not to tamper with the rhythm underway across the segment. And the third choice would have been to delete all instances of the conjunction entirely: old books, fine wine, good friends, conversation, festivity, laughter, a choice similar to the first arrangement, but even more intense in its coldish objectivity.
So what to do? The writer settled on a combination of the second and third choices as a complementary way of defeating the shortcomings of each: the first three items are joined by the conjunction (old books and fine wine and good friends) and the second three are not (conversation, festivity, laughter). The prevalence of conjunctions (a figure of speech called polysyndeton) speeds the first half of the line and mimics the familiar tone of easy conversation, perhaps a tempo close to what musicians call adagio. In the second half of the line, though, the writer has deleted all the conjunctions (another recognized figure of speech, called asyndeton), and the result is a braking or slowing as the sentence concludes with more consequential ideas. The final, combined effect of the style, then, is to move briskly from things to the more solemn pronouncements of conviviality and celebration—such was the human and civilized character of the friend being described.
The figures of speech, like polysyndeton and asyndeton, are best thought of as configurations, patterns of words and phrases and clauses that call forth certain emotional responses from the reader. The technical names of the figures, of course, are merely a way of finding the device when we need to use it, but sometimes labels on boxes can be helpful. One fine work that explains the more common figures and gives a wealth of examples for each is Arthur Quinn’s Figures of Speech: 60 Ways to Turn a Phrase, 1993. As he says there, in studying these rhetorical figures “we are learning not about hypothetical structures in things, but about real potentialities within our language, within ourselves.”