To help readers, we punctuate for two reasons:
- To set the pace of reading
- To divide words, phrases and ideas into convenient spaces
You will punctuate with power and purpose when you begin to consider pace and space.
Think of a long, long, well-written sentence with no punctuation except the period. Such a sentence is a long, straight road with a stop sign at the end. The period is the stop sign.
Now think of a winding road with lots of stop signs. That analogy describes a paragraph with lots of periods, an effect that will slow the pace of the story. The writer may desire such a pace for strategic reasons: to achieve clarity, convey emotion or create suspense.
If a period is a stop sign, the comma is a signal to keep going but with caution — it’s a speed bump. The comma may be the most versatile of marks and the one most closely associated with the writer’s voice. A well-placed comma points to where the writer would pause if she were to read the passage aloud.
The semicolon is a “rolling stop.” More muscular than the comma, it is most useful for dividing and organizing big chunks of information.
The parentheses introduce a play within a play. Like a barricade in the middle of a street, the parenthesis forces the reader to drive around it to regain the original direction.
The dash is a tree branch in the road. But the dash has two brilliant uses. A pair of dashes can set off an idea contained within a sentence. A dash near the end can deliver a punch line.
The colon announces a crossroads. Here’s what it does: It announces a word, phrase or clause the way a trumpet flourish in a Shakespeare play sounds the arrival of the royal procession.
Taken from The Writer’s Workbench: 50 Tools You Can Use, a self-directed course by Roy Peter Clark at Poynter NewsU.