Many a reader is bound to balk at the premise of Ben Marcus’s second novel, “The Flame Alphabet”: In a United States bearing a vague similarity to the real thing, the speech of children kills adults. If this were a droll take on the wearing nature of parenthood, comical possibilities might present themselves. But the execution here is fairly sober-sided, leaving the premise to seem, in sci-fi terms, overtly dumb.

To a surprisingly successful degree, this iffy idea is carried quite a distance by Marcus’s skillful prose. The concept’s goofiness is mitigated by signals that this is not merely a dystopian novel, but an allegory about language. For the first half, owing to the high quality of the writing, I was able to park my skepticism about why, as the protagonist observes, “children’s language should be toxic while the language of adults was not. The acoustics were the same. . . . It doesn’t make any sense.” However, at the midpoint, something happened (not in the novel; indeed, nothing happens in the novel, which was part of the problem), and I suddenly would do anything to avoid reading this book: scrape the ashes from the wood stove, bury the organic waste in the compost pile. I still look back on those little respites, wind whipping my hair while fat pink earthworms squirmed in moldy cauliflower leaves, with grateful affection.

Sam and Claire are “forest Jews,” members of a sect that worships in secret over “Jew holes,” to which they affix gooey, gel-covered mouthlike mechanisms in order to listen to piped-in sermons. The sect is initially blamed for spreading a debilitating and potentially lethal “language toxicity,” whose symptoms include a hard tongue and “facial smallness.” But the caustic comments of the couple’s own obnoxious 14-year-old, Esther, are also making Sam and Claire sick. To save themselves from certain death, the parents abandon Esther and hit the road. Claire gets lost in the shuffle. While children are quarantined in camps, Sam is co-opted by a wicked research facility that experiments on poisoned grown-ups, trying to find a cure for a condition to which only children younger than 18 are immune. By now, the disease has evolved so that not just kid-speak but all language is kryptonite: adult conversation, text, signage, even gesture. Mutely, Sam does experiments on a host of arcane scripts and alphabets, looking for a new mode of communication that doesn’t make people throw up. Nothing changes, nobody talks and life is rubbish.

Allegory or no, “The Flame Alphabet” does bid to function as quasi-science fiction, but the plot fails to develop, to take any firm turns and end up somewhere else; yet a payoff, twist or resolution of some description is a formal obligation of the genre. Accordingly, the book also falters on the allegorical level. Marcus makes numerous intriguing thematic comments in the course of this nominal story. Decried as “a coffin,” language “happens to be a toxin we are very good at producing, but not so good at absorbing.” Yet without this inadequate “extraction tool . . . one sensed that the whole enterprise of consciousness had suddenly lost its way. Without a way to say it, there was no reason to even think it.” Thus in the big picture, the author lurches uncertainly between “why don’t we all shut up” and “without language, we are brute animals, lacking identity or perception.” There’s no need for the novel to reduce to a single aphorism, of course, but the sensation of being trapped in a giant metaphor is so pervasive that it’s impossible not to fashion little theories along the way.

For example, because Marcus’s first novel played with similar ideas — “Notable American Women” concerns a feminist cult called the Silentists, who also eschew speech — one is tempted to hypothesize that this author is ambivalent about his craft. Is the churning out of still more text really what the world needs? Isn’t language a form of pollution? (Marcus’s parallel America has radio and television, but there’s no mention of the Internet — a conspicuous omission in a novel in which proliferating prattle is poisonous.)

“The Flame Alphabet” is Ben Marcus’s second novel. (Knopf/Random House)

For me, “The Flame Alphabet” triggered the very allergic reaction to verbiage that it describes. A relentless sameness to the drear, queasy atmosphere is stifling: Page after page, characters sicken in an unremitting assault of pus, pallor and hair loss. The imagery is monochrome: muddy and brown and cold. The nausea is contagious. The worms in my compost were positively perky in comparison to this enervating prose.

Marcus is a fine technician sentence by sentence, and there are some great lines here: “Claire tucked some cookies in her mouth, moving them around with her tongue as if they had bones.” But even an experimental novel that employs a sci-fi conceit needs to do something with the premise. Instead, this author successfully creates a self-contained alternative universe that’s disgusting, and then nothing happens aside from that universe becoming a little bit more disgusting. The result is a frantic desperation to escape. Perhaps I should thank him. My house is so tidy now.

Shriver’s 10th novel, “The New Republic,” will be published in April.

The Flame Alphabet

By Ben Marcus

Knopf. 289 pp. $25.95