Mark Wahlberg knows better than to do star comedies built around whatever character he’s playing. Buddy comedies are what work for him, mostly ones co-starring Will Ferrell. It takes the right “buddy” to get him wound up, antic and funny.

Rose Byrne takes on that role in “Instant Family,” an in-over-their-heads adoption comedy from Wahlberg’s “Daddy’s Home” team. And the two, playing overmatched adoptive parents, really wind each other up. The manic patter, voices rising in volume, the eyes bugging out hysterics generated by these two — especially Byrne (“Bridesmaids,” “Neighbors”) — deliver big laughs in between the warm fuzzies of what turns out to be a sentimental but sober look at adoption, with lots and lots of swearing.

Oh yeah, Hollywood’s reflection of the culture it works in has been free and loose with the PG-13 profanity, parents cursing around, cursing to and cursing-out their kids in screen comedies the past few years. It’s a reflection of what you run into in theme parks and fast food joints. It’s as if “The Bad News Bears” had replaced every child-rearing book on the market as the instruction manual for how to talk to your children.

In “Instant Family,” the cold slap of “This is what a FAMILY holiday comedy sounds like, now” sinks in when little first-grader Lita (Julianna Gamiz) turns to her adoptive mom, who is denying her a new cut-rate Barbie at the store because she already has a more “body positive” dolly at home, lets loose.

“You body positive whore!”

Kids cussing — low-hanging fruit, but always worth a laugh.

Ellie and Pete are successful California house-flippers, never giving much thought to kids until her competitive sister (Allyn Rachel) and obnoxious brother-in-law (Tom Segura) bait them into a fight over their latest too-many-bedrooms-for-them-to-need fixer-upper. That’s right, the Wagners are shamed into wanting kids.

And Ellie, trying to ease herself into this idea, makes the mistake of checking out “Who’s up for adoption” on a website, and next thing you know they’re taking “certification” classes from Octavia Spencer and Tig Notaro, making tactless cracks comparing kids to dogs (that website uses the “Adopt this Dog” website model), insulting their fellow prospective parents and swinging between petrified and “What’s the big deal?” with regard to the Big Change that is Coming.

Their parenting on a dare extends to who they zero in on at the local “adoption fair.” Yes, they’re totally a thing and yes, that’s exactly what shelters do with dogs in need of a home. Nobody else will talk to the teenage foster children, so that’s what Self-Righteous Pete and Ellie will do. That’s a cute running gag, that these two like how adoption makes them look generous, magnanimous even.

Sassy Lizzie (Isabella Moner of “Sicario: Day of the Soldado” and “Transformers: The Last Night”) doesn’t scare them off. Even the news that she comes with two younger siblings is just a doubling down on the dare. The Wagners bring home tantrum-tossing Lita and accident-prone, scared-of-his-own-shadow Juan (Gustavao Quiroz) and figure that love, generosity and civility will win over these traumatized-by-the-system children of a crack addict.

Right.

The producers figure they earn a pass on all the adult language and adult subject matter (Lizzie’s sexting flirtation with a 22 year-old) by giving a scruffy, rude picture a nice gloss of good intentions. Spencer and Notaro’s characters give solid statistics and blunt reality checks in between sarcastic riffs on adoption and how it’s not for everyone.

Moner’s Lizzie is quick to play the “poor orphan/hard life” card when her insolence is challenged. How do you pick a foster kid out in a crowd? Look for the child “carrying her whole life around in a Hefty bag.”

That may work on Granny Jan (Julie Haggerty, funny), but not on smothering Earth Grandmother Sandy (The Great Margo Martindale).

The grim keep-kids-for-a-paycheck foster parenting system earns a few shots, and there are slapstick accidents, dining disasters and department store meltdowns. The birth mother’s return signals court scenes — there’s a genuine effort to get a taste of the entire process in “Instant Family.” Too much effort.

But every so often, Byrne’s eyes bug out even wider than Wahlberg’s, her voice goes even higher and her patter outruns his in a sprint and she…just…loses…it. Goes off. She is hilarious in this, with a script that lets her lull us with how sweet and reasonable Ellie is, until she reaches her limit.

Or until somebody — sister, mother, adoption agent or out-of-control-kid — baits her.

“We could have had a little toddler who doesn’t have OPINIONS or THONG underwear!”

In the roller coaster between serious and silly that “Instant Family” bounces along on, Byrne is the Fast-Pass holder, and she makes this uneven dramedy a hoot, and more importantly, makes it work.

MPAA Rating: PG-13 for thematic elements, sexual material, language and some drug references

Cast: Rose Byrne, Mark Wahlberg, Isabela Moner, Octavia Spencer, Tig Notaro, Margo Martindale, Julie Hagerty, Joan Cusack

Credits:Directed by Sean Anders, script by Sean Anders and John Morris. A Paramount release.

Running time: 1:57