The oldest continuous chamber-music festival in America continues its season. In the second series of Young People's Concerts, harpsichordist Andrew Appel, artistic director of the Four Nations Ensemble, will present a performance that poses the question: "What makes it French?" (Sat 14). Later that evening, the Four Nations Ensemble will perform a Bastille Day concert celebrating the French Baroque repertory with soprano Dominique Labelle. Brilliant young piano trio Latitude 41 makes its Maverick debut with works by Schubert, Saint-Saëns, and Tchaikovsky on Sun 15. See maverickconcerts.org for details and travel information.