Weathervane Playhouse, a Knight Arts grantee, begins its 78th season by taking a dramatic leap with Tracy Letts’  “August: Osage County.”

The Pulitzer Prize- and Tony-award winning play is a taut, gruff, polished comic tragedy — that is, a play where you laugh yourself right up to the uneasy, unsettling final moments where bleakness prevails.

Weathervane Playhouse has notices out that this play is for mature audiences. On opening night, executive director John Hedges cautioned viewers about the rough language they were about to hear. The words were all there — most of George Carlin’s famous seven that can’t be said on television and a whole bunch more. But, as one person said during the first intermission (there are two in this three-and-a-half hour-long play), “Everybody hears that nowadays.” It’s probably true.

However, Hedges rightly noted that the language befit both situation and character in the play.

Letts’s drama covers an ironic take on “happy families are all alike,” if by that you mean they have stories and secrets of: divorce, marital infidelity, suicide, unknown siblings, drug addiction and alcoholism, recreational drug use, greed and a host of emotional failures. This extended family (of the Westons and their kin) would be a psychologist’s playground of dysfunctional family and personal relationships.

Harriett DeVeto as Violet Weston in “August: Osage County.” Photo courtesy of Weathervane Playhouse

Yet it’s hysterically funny in the telling (in the OMG way that you might have in the online world). Maybe we’ve all brushed against the edges of dysfunction and have felt its threat; the amazed or uneasy laughter may stem from that. Whatever, it’s great storytelling  — and great acting by this large and talented cast that director Jacqi Loewy has put together.

Harriett DeVeto is astonishing and magnificent as Violet Weston, the matriarch of the clan. Whether swirling around the stage in hazy pharmaceutical delusion, or grim-lipped and nasty when exposing family history, DeVeto takes the stage the way the character controls the lives of her children and other relatives. She knows all the secrets — where her husband was before his suicide, his philandering with her sister and the child they produced, whom her one daughter wants to marry, and the divorce of another daughter. All these, while possibly admirable if protecting her children, eventually becomes her undoing as the truth wills out.

Laura Stitt (as middle daughter Ivy) rings steady and true as her character barrels ahead to have a normal and reasonable life despite her family.

Tari Lyn Bergoine (as eldest daughter Barbara) tosses cleverly back and forth as the vulnerable wife and mother through impending divorce and the tough-as-nails eldest child who screams that she is in charge at the end of Act II  — right as the Weston’s house of cards is about to come tumbling down.

Harriett DeVeto as Violet Weston and Tari Lyn Bergoine as eldest daughter Barbara Fordham in “August: Osage County.” Photo courtesy of Weathervane Playhouse

Tom Stephan (as uncle Charlie) quite rightly stopped the show on opening night with his hilarious delivery of a halting and faltering grace for the meal this strange clan tried to have together. Anyone who has been put on the spot can feel for him.

“August: Osage County” will run through September 23 at Weathervane Playhouse, 1301 Weathervane Lane, Akron; 330-836-2626; www.weathervaneplayhouse.com. Performances are Thursday at 7:30 p.m., Friday-Saturday at 8 p.m., and Sunday at 2:30p.m. Tickets are $21.