Considering that a large part of my job revolves around grammar, I’m somewhat more laid-back about certain rules than one might expect. Or rather, like most people who traffic professionally in the English language, I have a set of rather idiosyncratic preferences that may or may not align with what most people imagine a member of the grammar police would take people to task over.

If, for example, someone assures me that they would never, ever end a sentence with a preposition or split an infinitive, my response is, well, “meh.”

One of my biggest pet peeves, however, involves dependent clauses—specifically, ones begun by subordinating conjunctions—and commas. Or rather, the lack thereof.

Common subordinating conjunctions include:

By definition, a clause that begins with one of these conjunctions (e.g., because I overslept,  after the movie ended, when the teacher handed the test back) cannot stand alone as a sentence—that is, it is dependent.

A dependent clause can, however, be attached to an independent clause to form a full sentence, e.g. Because I overslept, I was late for classor, We went to dinner after the movie ended.

Notice that in the first example above, the dependent clause comes before the independent clause, whereas in the second example it comes afterward.

Notice also that the first version contains a comma after the dependent clause, whereas in the second version no comma appears before the dependent clause.

I’ve written before about the ambiguities involved in using commas before this type of dependent clause. In general, it is conventional to place them before “strong” subordinating conjunctions such as (al)though and whereas, and to omit them before weaker ones such as when and until.

So, for example, you would write, We entered the theater when the movie began, NOT, We entered the theater, when the movie began. The comma in the second version creates an unnecessary and unnatural break.

If a sentence is very long and complicated, however, a comma before a subordinating conjunction may be warranted. It’s a judgment call, not a hard and fast rule.

The opposite, however, is not true.

When a dependent clause begun by a subordinating conjunction comes before an independent clause, the comma after the dependent clause is not negotiable.

Note that the rule is the same for other types of dependent phrases that often appear the start of a sentence, e.g., at first, generally speaking, in mid-2015. But because these types of phrases are short and more clearly set off from the rest of a sentence, they tend to pose less of a problem from a punctuation standpoint—it seems more obvious to set them off with a comma. In contrast, clauses begun by becauseor whenmay be quite long, the punctuation governing them less instinctive.

That said, setting off dependent clauses with a comma is not about nitpicking or following grammar rules “because they’re the rules”—it’s a matter of readability and courtesy to the reader. This principle is magnified in academic writing, particularly when complex ideas are involved:

Compare following sentences:

No comma: Because teenagers still face the choice of whether to be true to themselves or to conform to what others expect of them the novelThe Chocolate War (1974) remains relevant today.

Comma: Because teenagers still face the choice of whether to be true to themselves or to conform to what others expect of them, the novelThe Chocolate War (1974) remains relevant today.

No comma: Although Doris Lessing and Solomon Asch both suggest that people desire independence yet yield to conformity Asch’s experiment adds specificity to Lessing’s claims.

Comma: Although Doris Lessing and Solomon Asch both suggest that people desire independence yet yield to conformity, Asch’s experiment adds specificity to Lessing’s claims..

Notice how in each example above, the comma makes clear the division between the two parts of the sentence and helps to emphasize the logical relationship between them (cause and effect in the first example, contrast in the second).

Without the comma, the two parts of the sentence slide into one another, forcing the reader to stop and figure out where one thought ends and the next begins. This is fundamentally unfair to the reader, who should not be burdened with making an effort to work out what the writer meant. Rather, it is the writer’s obligation to make the divisions between thoughts clear so that the reader does not have to expend unnecessary mental energy to follow.

When commas are used well, they blend into the background—the written text mimics the natural pattern of speech and/or the logical progression of thoughts so seamlessly that the reader does not even notice the punctuation.

This apparent naturalness can, however, become a double-edged sword: because well-punctuated writing seems so easy and natural, it can inadvertently promote the misconception that writing well iseasy and natural. The problem, of course, is that while these rules are absorbed intuitively by some writers—a not insignificant number of whom are, not coincidentally, voracious readers—many other people must be specifically taught them in order to be able to produce even minimally effective prose.

If one falls prey to the illusion that good writing is effortless to produce, however, then discussions of subordinating conjunctions and dependent clauses might seem like a pointless technical distraction, one that serves only to make the composition process overly and unnecessarily complicated and artificial. (This is essentially the grammar equivalent of the phonics vs. whole language debate: if students are exposed to high quality writing, they’ll absorb the rules of grammar naturally. Umm… that’s not always how things work.)

I think the only way around that trap is to focus on the pragmatics. To treat grammar as a series of discrete rules to be memorized, without any underlying logic, is to largely miss the point of the subject. To be sure, there are some aspects of English, primarily involving idioms, that evolved the way they evolved for no particular reason; however, grammatical rules are by and large conventions that eventually hardened into fixed practices because they facilitated communication in some way, e.g., by marking the logical separation of ideas within a sentence. If students are guided to understand the reasoning behind various rules–that is, to understand that they aren’t right or wrong simply because “the teacher said so” (even if an increasingly small number of teachers do in fact say so, or perhaps even know what the conventions of English are themselves)—then they are more likely to retain important concepts, and to be able to employ them effectively in their own writing.