By Siddhartha Mitter, Globe Correspondent

SOMERVILLE -- "I don't know how I became a diaspora," the Haitian roots diva Emeline Michel mused onstage, her novel use of the collective concept somehow sounding just right. "It seemed to happen all of a sudden." Many in the enthusiastic, largely Haitian crowd gathered at Johnny D's on Thursday night could surely relate to the New York-based singer. She brought them home with a polished performance that grew more organic as the night went on.

A poised performer, Michel was almost too prepared for the show. She introduced the early songs with whimsical recollections of life in Haiti that rang a bit false, as if overly scripted. And despite its sexy theme and fast, rootsy rhythm, "Il fait chaud," an ode to undressing on the beach, fell a little flat, the dance floor not yet primed for such fare.

An inspired sequence soon fixed that. "La Karidad" lauded Port-au-Prince's hardscrabble districts over guitar polyrhythms in the style of defunct maestro Coup Clou; the reliable anthem "Haiti chrie" followed. And when her 1987 breakout "Plezi Mize" ("pleasure in misery") broke down into a hard, clean kompa rhythm, the crowd's assorted fedoras, microbraids, and head-wraps bobbed in unison while Michel undulated onstage.

Michel frequently acknowledged her musicians, with good reason. The six-piece combo glided easily from relaxed twoubadou, not unlike Cuban son and rumba, to furious licks over cascading African beats. On one guitar, Makarios Csaire deftly blended a solo fit for a rock power ballad into a laid-back tropical shuffle. Dominic Kenza, on the other, excelled in the soukous crescendos of his native Congo, at once frenetic and sweet.

Indirectly, Michel evoked Haiti's troubled state: The nation marked, this year, 200 years of independence with an armed insurrection and calamitous weather. A mudslide set in motion by Hurricane Jeanne virtually leveled Michel's home town, Gonaves. Presenting the prayerful "P Ltnel," she called on her audience to remain strong.

But her liberation message was all about spirit and body. No shabby dancer and not at all shy, she flirted and shook just inches from the audience, compounding the intimate feel that is the venue's greatest asset. The syncretistic rara, a Vodoun-based rhythm performed during Lent, propelled her hips into the staccato sway known as "gouyad."

While the band stilled, Francois Sergo Dcius on percussion excavated the beat, and Michel channeled it in a kinetic frenzy. "This is my personal loup-garou [sorcerer]," she said, emerging from the dance.

At that moment, it did not need explaining.