THE ROSTER for Saturday's Third World Unity Festival reads like a summit meeting of the rulers of "world music": the assembled eminences include Nigerian juju ruler King Sunny Ade, Jamaica's Burning Spear, Haiti's Tabou Combo and the West Indies' Mighty Sparrow, who claims the title "calypso king of the world."

Mighty Sparrow, aka Slinger Francisco, has for years been a consistent victor at Trinidad's annual Carnaval song competition, where a song's message is just as important as its danceability. So within his insistent rhythms, "The Bird" slyly layers in themes of local injustice and international intrigue. His latest release, "One Love, One Heart," finds him in a more humorous vein, as he tries to fast-talk his way out of a tussle with his suspicious girlfriend in "Lying Excuses," and wittily chastises a rascally politician in "Bald Head."

The buoyant and brightly colored polyrhythms are like a Caribbean vacation on vinyl, with newfangled touches like Linn drums and synths simmering beneath the traditional steel drums, chattering horns and scratching guitars. MIGHTY SPARROW --

"One Love, One Heart" (B's Records SP-069). Appearing Saturday with King Sunny Ade, Burning Spear and Tabou Combo at D.C. Armory.