About half-way through this past school year I decided to ban my sixth- and seventh-grade English students from using that mea culpa of the new millennium, the phrase “my bad,” to admit to any kind of mistake or failure. This came right after I banned them from using the word “like” as if it were a kind of verbal punctuation mark (as in the typical middle schooler sentence: “Because, like, you know, like, I don’t, like, really like like him—I just kinda’ like, like him.”).

My reasoning was, I thought, both pertinent and straightforward. Lacking a verb and subject, “my bad” is merely a phrase containing two common adjectives and thus is not a real sentence. When words and phrases go around masquerading as sentences, I teach my students to stop them dead in their tracks, properly identify them as fragments, handcuff them to the nearest sentence diagram, and as duly-deputized members of the grammar police, fill in the missing blanks.

And then one day my principal came into my seventh grade grammar class, and within a short time one of our nimble-minded students caught her in a mistake, to which she promptly replied, “My bad!”

I could see where this was heading. Middle schoolers are not the kind of people to let an opportunity escape or an advantage slip through their fingers. So I quickly spoke up.

“Uh, I don’t allow people to say, ‘My bad,’ in my class,” which, of course, I said for the benefit of those students (specifically, all of them) who would try to use an incident involving the principal as leverage.

She instinctively responded, obviously before thinking it completely through, with, “Oops! My bad!” and it seemed that all was lost.

But eventually it dawned on me that perhaps my approach had been a tad hard nosed. After all, we use sentence fragments in conversation all the time. Even some of today’s best selling literature is replete with them. Heck, if you removed all the sentence fragments from Rob Bell’s Velvet Elvis, you’d end up reducing it to the size of a handy church bulletin supplement!

We also teach our students to supply implied words in sentence diagrams in order to make the clearest possible sense out of sentences that normally leave out, for example, second-person personal pronouns with imperatives (as when we say, “Watch out for that road apple!” instead of “You watch out for that road apple!”). In such cases, as I’m sure you all remember, we put the implied word “You” in parentheses—“(You)”— in the subject part of the diagram.

Take the simple reply, which I actually accept in lieu of “my bad,” that a student invariably utters when he or she accepts blame for some trivial thing by saying, “Sorry!” The word “sorry” here is merely an adjective (although it is seldom an apt description of the true demeanor of the student), but with the proper application of the latest grammatical technology we could diagram this fragment as if it were a complete sentence as follows:

Suddenly it becomes obvious that “sorry” is not merely an adjective, but a predicate adjective with an implied subject, “(I),” and an implied linking verb, “(am).” But the pressing question here is whether or not we can rehabilitate “My bad” in similar fashion. If we could, the diagram would look like this:

The problem with this option is immediately obvious to those of you who stayed awake during junior high school (or middle school) English: we seem to have one adjective, “my,” modifying another adjective, “bad.” Adjectives do not modify other adjectives; adverbs modify adjectives. So, unless “my” can be an adverb (which it cannot), “bad” cannot be a predicate adjective, and so our first move might be to get it out of the predicate position on the diagram.

But then what do we do?

Well, to begin with, instead of looking to the expression, “Sorry,” for clues on how to diagram “My bad,” perhaps the sentence, “That was my fault” (sometimes abbreviated to the fragment, “My fault”), might provide a more suitable model. It would be diagrammed virtually identically to what we have above:

The only difference here is that, as it is a noun, “fault” is a predicate nominative, and since we have already decided to take “bad” out of the predicate position because it’s modified by “my,” we could assume that both “my” and “bad” are modifying yet another word that is only implied in the sentence. Let’s assume it’s the word “thing,” so we would then make the following diagram:

Not exactly an elegant solution, is it? But there is one other possibility. We do occasionally use the word “bad” as a noun signifying “that which is bad” (cf. The American Heritage Dictionary of the English Language, [New York, NY, USA: American Heritage Publishing Co., Inc., and Houghton Mifflin Company, 1970], 98), as in the expression “weighing the good against the bad,” or the movie title, The Good, The Bad, and The Ugly. While we almost always use the definite article (“the”) to signal that we’re using “bad” in this fashion, I don’t know of any rule that requires it. So if you don’t like the idea of “My bad” consisting of two adjectives modifying an implied noun, you could assume that “bad” is actually being used as a noun and fall back on our previous diagram:

Only this time “bad” is assumed to be a predicate nominative instead of a predicate adjective.

And so, there you have it. Perhaps I should apply for a government grant to fund several years of research to determine which of the above two diagrams is correct, but right now I need to grab a cup of coffee.