LED BY folklorist and fiddler Michael Doucet, Beausoleil has evolved into Louisiana's leading ambassador of cajun music. What makes the group's new album, "Allons a Lafayette," such a delight is that this cajun quintet's love for the old songs and style is only the cornerstone of their adventurous music.

For example, in the midst of this collection of traditional cajun two-steps, waltzes and ballads, the band lets creole fiddler Canray Fontenot join them for a low-down blues, "Les Blues a Canray," that pits Fontenot's raw fiddle against Sonny Landreth's stinging slide guitar. Fontenot is no less ingratiating on "Shoo Black," a boozy country ditty about a thief after someone's hogs and billy goats.

Like all cajun groups, Beausoleil is primarily a dance band. Whether it's the classic two-step, "Allons a Lafayette," or a waltz, "La Jolie Blonde," Doucet's lyrical fiddle and Errol Verret's wheezing accordion create a simple but irresistible momentum. You may not understand a word of Doucet's high-pitched French singing, but the sad songs feel sad and the happy ones speak to the feet in a universal tongue. BEAUSOLEIL -- "Allons a Lafayette" (Arhoolie 5036); appearing at the Birchmere Saturday night and at a 7 p.m. "Twist & Shout" dance at the Bethesda American Legion Hall Sunday night.