Mya Arulpragasam has a habit of scrunching up her mouth. In photographs, she often pulls her purple- or orange-painted lips into a punk's sneer — a bit of old Sid Vicious creeping into the visage of this 30-year-old, London-born, frequently displaced daughter of Sri Lanka.

Her voice, at the center of her continent-hopping, beat-happy songs, emerges from that wry face. It's not always easy to take or, for some, to take seriously.

Despite being universally praised as a harbinger of pop's future, M.I.A. (as Arulpragasam is known) often is dismissed as a vocalist. As "Kala," her second album, hits American retail outlets this week, its reception is another case in point. Even reviews that say "Kala" could be the release of the year use words such as "flat" and "limited" to describe M.I.A.'s voice.

This is minor stuff, as M.I.A.'s voice is just one element in her efforts to expand dance-floor consciousness. Made while she traveled the globe after being denied entry to the U.S. (visa problems sabotaged a collaboration with Timbaland — lucky her, because the one track they did make is the album's worst), "Kala" incorporates field recordings that M.I.A. made in India, Australia, Trinidad and Japan.

The production, by M.I.A. and a select crew — London-based "fidget house" originator Switch, Baltimore DJ Blaqstarr and Diplo, M.I.A.'s Philly-based former partner, now estranged — draws on a wide array of sounds and nightclub trends. There are Bollywood hooks and Tamil Nadu village drums; the spaciousness of dub and the relentlessness of Baltimore thump beats; the lilt of Caribbean soca, and whimsical references to indie rock icons Jonathan Richman and the Pixies.

From the chicken cackling and children's shouts on "Birdflu" to the gunfire and cash-register rings that punctuate a Clash sample on "Paper Planes," the music on "Kala" is truly multivocal. Every sound signifies something different, driving the music's meaning into some new corner.

To dismiss M.I.A.'s voice is to miss the whole point of "Kala." The album hits hardest by embodying the process by which certain voices are bottled up and distorted within the global noise of what M.I.A. calls "Third World Democracy."

M.I.A.'s music strives to make sense of that cacophony, and the first voice she seeks to free is her own.