In SpeakEasy’s ‘Once,’ pondering what might have been

Mackenzie Lesser-Roy and Nile Scott Hawver in “Once.” Maggie Hall

From start to finish in Paul Melone’s SpeakEasy Stage Company production of “Once,’’ the charms of this Tony-winning musical battle with its limitations. Overall, I’d say it’s a draw.

First, those limitations: Look closely at “Once,’’ and you’ll be struck by how many emotional shortcuts it takes, how strenuously it tries to be adorable, and how thin its storyline is. Narrative arc? Not so much. Incisive lyrics? Sometimes, sure, but at other times they have a by-the-numbers predictability. In-depth exploration of its two lead characters? Not really.

Now, about those charms: When “Once’’ is at its most beguiling, it floats on the currents of gorgeously wistful melodies that communicate — better than any words could — the ache of finding the right person at the wrong time. They give the musical an elegiac undertow that alternates between what-might-be and what-might-have-been and does legitimately tug on the heartstrings.

And when it comes to this SpeakEasy production, “Once’’ is further buoyed by Mackenzie Lesser-Roy’s note-perfect performance as an enigmatic but generous-spirited Czech immigrant in Dublin, identified only as Girl. Acting as a muse to a heartsore Irish street musician who is working as a vacuum cleaner repairman, Girl helps him see his possibilities as a songwriter and singer while discovering something about her own musical potential as well.

Nile Scott Hawver’s portrayal of that doleful busker, identified only as Guy, is a mixed bag. While Hawver captures Guy’s lost air of unsettled despondency in the aftermath of a romantic breakup, the actor does not demonstrate the vocal chops to really put across songs like “Leave’’ and “Say It to Me Now,’’ neither of which register here with the raw force of anguish they require.

Not so with Lesser-Roy, yet another talented graduate of the Boston Conservatory to shine on a local stage. Her Act 1 performance of “If You Want Me’’ is an exquisite blend of ethereality, sensuality, and yearning. When she sings “Falling Slowly’’ in a duet with Hawver, and in a later reprise of that song with him and the ensemble, Lesser-Roy gives the song a stirring power.

That’s the best-known song in “Once,’’ whose score is the creation of Glen Hansard and Markéta Irglová, with a too-glib book by playwright Enda Walsh. It’s been an eventful decade-plus for this modest tale. After originating as a 2007 film starring Hansard and Irglová as Guy and Girl, the musical adaptation of “Once’’ was developed in a workshop at the American Repertory Theater in the spring of 2011, then opened on Broadway the next year. In 2012, the show walked away with fully eight Tony Awards, including best musical. Steve Kazee and Cristin Milioti were so good as Guy and Girl that their shadows have loomed over subsequent productions of “Once.’’ The show ran for three years and nearly 1,200 performances on Broadway. A national tour came to Boston five years ago.

In the 2016-17 national tour of “Once,’’ Lesser-Roy portrayed Girl, and her experience shows in the absolute assurance with which she inhabits the role at SpeakEasy. Girl is a tricky character, always teetering on the verge of overly precious whimsy, but Lesser-Roy, crucially, does not overplay the quirky-waif aspects. Even when Girl is just standing pensively, hands in the pockets of her short jacket as she watches Guy perform, Lesser-Roy communicates an ineffable weight of feeling.

Director Melone demonstrates equal finesse both when it comes to handling the scenes of swirling action in a Dublin pub and the moments of contemplative stillness that unfold to the lovely sound of songs like “The Moon’’ and “Gold.’’ Music director Steven Ladd Jones ensures that all the colors of the “Once’’ score are fully heard, and Ilyse Robbins has devised boldly distinctive choreography that brings the stage to flowing life.

The ensemble does terrific work, especially considering they are also required to play musical instruments — a first in the 27-year history of SpeakEasy. Billy Butler is a scene-stealing treat as an outwardly gruff piano store owner who is protective of Girl, and the production also benefits from the presence of Kathy St. George as Girl’s mother, Billy Meleady as Guy’s father, and Jeff Song as a bank manager. The bank manager seems like a staid guy at first, but he’s got something to say, and like everyone else in “Once,’’ he wants to say it in song.

ONCE

Book by Enda Walsh. Music and lyrics by Glen Hansard and Markéta Irglová. Based on the movie written and directed by John Carney. Directed by Paul Melone. Music direction by Steven Ladd Jones. Choreography by Ilyse Robbins. Presented by SpeakEasy Stage Company at Roberts Studio Theatre, Calderwood Pavilion, Boston Center for the Arts, through March 30. Tickets: From $25, 617-933-8600, www.SpeakEasyStage.com