Sceptre £16.99 pp373

As a novelist, David Mitchell has always seemed curiously loth to speak in his own voice. Ghostwritten wasn’t just the title of his first book but a proclamation of what would follow. Imitating other people’s tones, accents and idioms has been his stock in trade (his last novel, Cloud Atlas, had six different narrators). Black Swan Green reveals what lies behind this ventriloquism.

Palpably autobiographical, it is narrated by Jason Taylor, a teenager in a Worcestershire village in 1982, as Mitchell was. Again like Mitchell at that time, Jason is racked by a severe stammer. Unnerving speech blockages sabotage his answerings of questions in class. Being required to read aloud at assembly provokes panic. Words beginning with n, s and y loom like cruel instruments of torture.

Jason’s battle against this impediment constitutes the most involving aspect of a novel everywhere concerned with communication and non-communication. What can and can’t be said (metaphorically as well as literally) is the pervading theme. Specious speech — rhetoric, evasion, pomposity, lies, bluster, blarney — is rife. Among Jason’s schoolmates, whole tranches of language — particularly words associated with emotions or art — are jeeringly dismissed as “gay”. Using past-its-shelf-life slang (“No one . . . says ‘epic’ any more”) is social suicide.

In the adult sphere, too, what people do or don’t say can be crucial. The story opens with Jason picking up a ringing phone in his father’s study, only to sense someone listening but not answering. The secret affair this is the first inkling of becomes increasingly perceptible through lowered parental voices, choked-off remarks and conversations harsh with animosity. Discord jangles the wider world as well. Thatcherism’s dictates stridently divide society. The Falklands war triggers bellicose brayings from the right-wing press.

To ease the frustrations of his stammer, Jason has cultivated a literary voice (“Only in my poems . . . do I get to say exactly what I want”), secretly submitting verses to the parish magazine. Improbably on hand to offer helpfully caustic comments on them is a flamboyant Belgian grande dame, Eva van Outryve de Crommelynck (who appeared as a girl in Cloud Atlas). Her function is to chivvy Jason towards a more honest style. Simultaneously, the plot — full of bullying and cowardly hushings up — steers him towards bravely speaking out.

Ironically, the book’s biggest obstacle to giving plausibility to all of this is its inability to sustain a believable narrative voice. Even allowing for the oscillations of adolescence, Jason is an exceptionally inconsistent 13-year-old. Mitchell catches the callowness but can’t resist endowing his hero with the insights and cadences of a literary veteran. Jason dispenses aphorisms as if he were a juvenile La Rochefoucauld: “Human beings need to watch out for reasonless niceness . . . It’s never reasonless and its reason’s not usually nice.” High-flown phrasing (“Baptisms of fire cause third-degree burns”) is another speciality.

As if recognising the artificiality of this, Mitchell strives to make his scenes more actual by piling them with solid detail. Commodity placement — Findus Crispy Pancakes, Angel Delight, Maryland Chocolate Chip Cookies, Marks & Spencer’s French Fancies — is on such a scale that pages can look like overloaded shopping trolleys. Television listings (“a glittery new quiz show called Blankety Blank”, Thunderbirds, Tomorrow’s World, Sesame Street, etc) are equally copious.

Heavy-handedness has always coexisted with structural niftiness in Mitchell’s fiction. Here, where clear-pane naturalism more or less replaces his usual arty mirrorings and refractions, crudities stand out more starkly. Points are hammered home: Jason is persecuted after stammering while reading Lord of the Flies to the class. There are other clunky ironies: “Worst that’ll happen to me is sunburn,” jokes a sailor bound for the Falklands on the doomed HMS Coventry. Dialogue often settles for over-the-top parody (“I wish to deposit words into your auditory organ”). Mitchell’s customary insistence that humanity is incessantly impelled to exploit and oppress seems banally repetitive and simplistic. Things end amid a rosy glow. Boldly giving voice to devastating truths, Jason leaps from pariah to popularity. Clocking up PC credits, too, for his enlightened attitudes, he acquires as a reward a girlfriend, whose tongue “visited my mouth, like a shy vole”. But the book’s satisfactions really derive from the light it casts on the shaping of an idiosyncratic literary imagination.

Available at the Sunday Times Books First price of £15.29 (including p&p) on 0870 165 8585

Times Recommends

• The 100 Best Books of the Decade
• The Times picks the 50 best paperbacks of 2009
• The conversation: James Ellroy