Quincy Tyler Bernstine, Hill Harper, Dierdre Friel and Kevin Isola in Our Lady of 121st Street at Signature Theatre.

I’ve been struck by how often Stephen Adly Guirgis—a much-lauded playwright in hip circles, who is featured this year at Signature Theatre—is praised for the authenticity of his street vernacular. Maybe, but since the comment most often comes from critics (which I mean here to be taken as code for mostly affluent and white), how exactly would they know?

I freely admit I’m not in a position to judge its accuracy, but what I hear is dialogue that feels highly constructed, with flashes of cleverness and wit, heavily laced with Guirgis’s signature barrage of expletives. It doesn’t suggest “authenticity” to me so much as the sassy cousin of funny TV writing, deliberately made racy for shock value.

Consider also some sample Guirgis titles. Our Lady of 121^st Street and Jesus Hopped the A Trains share the rhetorical flourish of coupling sacred and urban. The Motherfucker with the Hatcouldn’t be advertised without asterisks in the New York Times, which I suspect was the point. Domenica the Fat Ugly Ho speaks for itself.

I’ll admit I’m a sucker for a catchy title, and several of Guirgis’s have grabbed me as they’re meant to. The trouble is that although he’s an exceptionally good craftsman—adroit at telling a story and keeping a lot of (forgive the expression) balls in the air—his plays only intermittently go deeper than their surface shock tactics.

You certainly won’t find much depth in Phylicia Rashad’s flashy, shallow production of Our Lady, though Guirgis doesn’t help. Still, there are opportunities for pathos in this story where the funeral of a dead nun, Sister Rose, ignites a series of encounters with people whose lives were touched by her. These are troubled souls living on the margins, often with a sense that something dire is in the offing.

But from the get-go, Guirgis signals that seriousness will be consistently undercut with humor. Rose’s body has mysteriously disappeared—stolen, presumably, though why and by whom is an open question. And as the lights come up on the casket, a disgruntled man standing next to it is wearing no pants.

The next two hours are a rollercoaster ride, veering from comedy to tragedy. Or, at least, they should be. But Rashad’s direction inserts an unwelcome sense of jazz-hands flash into the short scene-lets, which here look more like the kind of miniatures specifically designed for acting showcases than part of a long, thoughtful story arc.

Joey Auzenne and John Procaccino in Our Lady of 121st Street at Signature Theatre.

A couple of ensemble members stand out for subtler and more nuanced work—particularly John Doman as a priest who questions his own effectiveness and Joey Auzenne as a detective with a haunted past. Quincy Tyler Bernstine somehow finds an essence of truth in the schtick-laden writing and direction. The others don’t fare as well and are sometimes undone by the awkwardly wide performance space of the Irene Diamond Stage, which further compounds the artificiality.

In the end, a production meant to celebrate Stephen Adly Guirgis’s importance and influence paradoxically reveals his faults. As seen at Signature, Our Lady of 121^st Street is perilously close to TV comedy, with the addition of a lot of dirty words.

Our Lady of 121^st Street plays through June 17. For more information, visit the Signature Theatre Center website.