Written language captures things that spoken language never could. Does anyone know, for example, what a semicolon sounds like?

Consider the sentence "Order your furniture on Monday, take it home on Tuesday." With a comma, it means that if you order your furniture on Monday, you can take it home on Tuesday. "Order your furniture on Monday; take it home on Tuesday" is different, however; it is a double command. But sometimes you can't tell the difference between the two sentences simply by hearing them read aloud. You need to see their punctuation to detect the difference.

If you look carefully, Mr. [Geoff] Nunberg said, the world of punctuation has its own rules of power politics. Commas are the weakest, semicolons are middleweight powers and colons are superpowers. Look more carefully and there is even a ranking among semicolons.