Let’s look at the language of a casual exchange between two managers about an employee who is regularly late to work. Having been told about the problem, one manager says, I’ll talk with him when he gets in, and the other replies, Yeah, well, when he gets in is just the question. Both sentences work just fine grammatically, and the second statement even exhibits a little sophisticated playfulness with the language. And it’s right there—in what’s happening in the second sentence—that we can learn something grammatical.
Straightforward remarks can often be fairly complex in structure, and that is the case with both these sentences. The statement I’ll talk with him when he gets in is made up of two clauses, one independent (I’ll talk with him) and the other subordinate (when he gets in). Sentences with both independent and subordinate clauses are classified as complex, but the grammatical gearwork of this complex sentence is fairly simple if we can keep our eyes on the two large sections of its composition: an independent clause followed by a subordinate clause.
Subordinate clauses act in their entirety like a part of speech, either noun, adjective, or adverb. So if we isolate the subordinate clause of this first sentence and ask what question it is answering (always a good way to discern the grammar of a sentence element), the first word of the clause gives us the answer: when. Elements that answer when are adverbial, so we can conclude that the verb of the independent clause (will talk) is being modified by the adverbial subordinate clause that follows it: When will I talk with him? When he gets in.
Let’s compare this now to the subordinate clause of the second sentence. The grammatical body of this statement begins after the first two interjections (yeah, well) with the same subordinate clause with which the first sentence ended. This in itself is a sharp rhetorical play, putting into proximity two elements used differently, but what exactly is the grammatical change that gives the reply some of its dash? Unlike its use as an adverb in the first sentence, this same subordinate clause is now set as a noun, standing as the subject of the verb is in the second sentence. What is it that is just the question? When he gets in. Nouns answer to the question what?
The clever (or maybe smart-alecky) reply rests structurally on the fact that what appears to be an adverbial clause is being used as a noun clause; and if we had to explain the construction more fully (and perhaps risk losing our sense of humor in the process), we could account for the transformation by seeing that the words the time (or something similar) have been omitted from the beginning of the clause: Yeah, well, the time when he gets in is just the question. In this more grammatically complete version, the noun time would be the subject of the verb is, and the subordinate clause would now be an adjective clause modifying the noun time. Such an omission (called ellipsis) is entirely regular in English, and makes possible much of what we do casually with the language.
And it’s right here that this kind of close analysis can bear fruit. We should have in our linguistic repertoire the ability to fashion sentences both formal and casual as the circumstances demand. Grammar worries over its rules, but rhetoric is attuned to effect, the way the meaning of a sentence lands (as actors say) on the audience. There can often be tension between the two forces, but they know in their better moments that each needs the other to represent a living moment in language.