Latin pop never quite became la juggernaut loca it promised to be, but, thankfully, groups like Texas' KUMBIA KINGS have continued to thrive. On the polyglot 4 (EMI Latin), the five-man boy band (founded by A.B. Quintanilla III, brother of the late Tejano star Selena) teases the old and young alike. For traditionalists, there's south-of-the-border roots music -- ''No Tengo Dinero,'' featuring El Gran Silencio, and ''Mi Gente,'' with Ozomatli -- and for their kids, the Kings sing radio-ready prom songs. The latter come in three styles: plaintive Spanish-language ballads like ''Rompecabezas''; crossover soul like the current hit ''Don't Wanna Try,'' by King Frankie J (whose solo debut is out this week); and such cheesy, timeless pop as a cover of New Kids on the Block's ''Please Don't Go Girl,'' updated with teenybop raps for multiculti baggy-pants appeal.