I once graded an essay so heavily marked with commas and apostrophes that it resembled a spray of ink dots more than it did writing. My student, pink with embarrassment, admitted his personal rule of thumb had always been to alternate “loads” of punctuation on one assignment with “zip” on the next. He assumed he’d be right about half the time either way.
How can anxiety over punctuation rules be avoided? Stop looking at sentences and wondering whether the correct rule has been applied. Instead, identify the core of a sentence and use its meaning to correctly punctuate the rest of it.
For example, “interrupter” (aka “island”) commas bracket an appositive, a parenthetical word or phrase, or a nonrestrictive clause. (Raise your hand if your eyes just glazed over.) In other words, the core sentence stops, expands, and restarts, so the commas are needed to signal there is an attachment. Think of interrupter commas as staples, or stitches, or even the old-fashioned brass clasps.
Correct usage of interrupter commas, however, does not require analyzing the parts of speech for the word(s) inside them. Instead, it requires knowing which of two things is true: either the interrupting words add nonessential information to the sentence or those extra words change its meaning. If it’s the former, use commas to alert the reader. If it’s the latter, the word(s) are not an interruption, they are a requirement; skip the commas.
The second sentence of this post contains an interrupter:
My student, pink with embarrassment, admitted …
“Pink with embarrassment” adds extra detail and removing it does not alter the meaning. See for yourself:
My student admitted his personal rule of thumb had always been to alternate “loads” of punctuation on one assignment with “zip” on the next.
See? The core of the sentence is the young man’s handling of punctuation. The blush description interrupts the sentence to provide extra detail. The temporary change of subject says that his attitude was apologetic rather than defensive.
Learn to think about punctuation as signals. While some marks have more than one use, all of them have a dominant use. If you learn those, all else can be double-checked in a handbook. The punctuation rules exist not to torture students (that is simply a side benefit), but to assist writers in making sentence meaning as clear as possible to readers. Want my help? I’ll post on each of the punctuation marks with examples, but for now see: comma use, punctuation for dependent clauses, or punctuation for the four sentence types.