Nueva cancion, a South American folk movement begun in Chile, Argentina, and Uruguay in the early 60s, brought a fierce political consciousness and an international flavor to various indigenous musical forms. Arguably the greatest and most important living exponent of this tradition, Argentina’s Mercedes Sosa has long been able to make nearly any sort of song all her own. Giving voice to the sentiments of her people got her in trouble in the late 70s– she was arrested, then exiled for a few years by the ruling junta–but that didn’t keep her from continuing to challenge the regime. Though she helped popularize the work of great Chilean songwriter and nueva cancion pioneer Violeta Parra and introduced the songs of Brazil’s Milton Nascimento to the Spanish-speaking world, she’s always emphasized music from her homeland, both preserving marginalized folklore and working with contemporary songwriters. Sosa’s most recent album, Corazon Libre (Edge, 2005), sheds light on lesser-known Argentine styles like zamba, milonga, and chacarera in a elegant, stripped-down setting, and her still-sublime voice lets her soar through epic drama and tiptoe through delicate balladry with equal ease. Guadalupe Pineda opens. a 8:30 PM, UIC Pavilion, 1150 W. Harrison, 312-996-3095, 312-413-5740, or 312-559-1212, $25-$75. A