Just about every parent has let an ill-advised word slip only to hear a cherubic voice (in my case usually from the back seat of the car) pipe up with “Mama, what does &^%$ mean?”

As is often the case, the issue remains as your children get older. When your kids are teenagers, as mine are, you have to decide when to turn a deaf ear to those words uttered by your former little darlings in your own house.

But swearwords and kids has long focused on the spoken word, a fleeting utterance that floats away on a breeze. Regrettable, but also ephemeral.

Now, however, at least two of George Carlin’s “Seven Words You Can Never Say on Television” have made their way onto multiple bestsellers lists: Justin Halpern’s “Sh*t My Dad Says” and Adam Mansbach’s hysterical parody “Go the F--k to Sleep.” Yes, profanity appears not just inside books, but on the covers. And that puts the discussion of swearwords and kids in another perspective.

Let me confess that when a colleague showed me the Mansbach book, which is a kind of mash-up of what happens when a crazed, sleep-deprived parent meets a whimsical bedtime story, the first thing I did was show it to my 15-year-old twin sons. There are no more sacred family traditions in our household than bedtime stories and the recounting of how I didn’t sleep for the first nine months of their lives. So we read the highly profane little book with its illustrations of cerulean night skies and wiped tears of laughter from our cheeks.

But I couldn’t get over the feeling that if I had come across this book in a store with young kids in tow, I would have felt far more uncomfortable about them seeing that word printed than I would have felt about them hearing the word in passing.

“Everything has a different effect when it is seen rather than heard. It is more shocking to see swearwords written out,” said Deborah Tannen, linguistics professor at Georgetown University and author of the groundbreaking book on the power of language “You Just Don’t Understand.”

Tannen contends that the “interesting phenomenon” of seeing swearwords in book titles is an “extension of how electronic media are evolving our thinking on what’s private and public. . . . There’s so much competition to get attention now that the more shocking uses are just another way to get our attention.”

But Tannen also focuses on the shifts in societal acceptability that the appearance of profanity on book jackets represents. “Remember, it has always been acceptable in certain contexts. What we are dealing with increasingly is the breakdown of the barrier between public and private. What we define as public and private keeps shifting and expanding,” she says.

There are those who will point out that the Halpern and Mansbach books, as well as Marcy Roznick’s recently released “If You Give a Kid a Cookie, Will He Shut the F--k Up?” don’t actually put the full words in question on the covers. But Mansbach and Roznick’s books could clearly catch the eyes of little kids who would be likely to ask “What does that say?” Which would be awkward, at least, for any grown-up.

Trust me, I know. While giving a tour of the Post newsroom to a group of 9- and 10-year-old Cub Scouts last week, one of them asked about a sign on an editor’s desk. “Why does that say ‘WTF?’ ” the fourth-grader in the badge-laden blue uniform inquired.

In that moment, I knew for certain that the written word — or even written letters — has a power that is hardly fleeting.

Tannen is, however, willing to put profanity on book jackets in context. “Kids are exposed to things more and sooner than they have been in the past. I’m not sure that language is the most distressing of all.”