Almost from the moment films could talk, they sang, which gives author Richard Barrios his text for a film-clip-laden chat about the birth of the movie-musical. “A Song in the Dark: The Birth of Musical Film” offers portraits of musical legends Fanny Brice, Maurice Chevalier, and Ethel Waters, as well as of such reluctantly vocalizing nonsingers as Gloria Swanson and Joan Crawford. At 8 p.m. at the Ripley Center, 1100 Jefferson Dr. SW. $13. For reservations call (202) 357-3030. (Bob Mondello)