After the Berlin Wall was demolished, signs were changed swiftly on the eastern-sector streets and public buildings that had been named for Lenin, Trotsky, and Mehring, but the parks and plazas bearing the name of Rosa Luxemburg remained untouched. As one citizen explained, she was "the revolutionary with the human face." This diminutive, semicrippled Polish-Jewish woman was no mere mascot, however: as early as 1903 she criticized Lenin's Central Committee for its terrorist tactics, foretelling the downfall of any government that could so compromise its principles under pressure of expedience. We learn all this and more in the course of Donna Blue Lachman's one-woman show The Language of Birds: Rosa Luxemburg and Me, written by Lachman and longtime collaborator Tim Fiori. Based on Luxemburg's letters from the prison where she was incarcerated by the German government for her antiwar activities just prior to her death at the hands of Nazi assassins, and on independent research done by Lachman, who in 1989 retraced the steps of her subject through Berlin and its environs, this remarkable portrait of the woman who would provide the prototype for female radicals has been newly revised to include more information about not only Luxemburg herself but her formidable influence on politics to this day. Anchoring the whole affair, however, is the astonishing portrait of Luxemburg Lachman creates onstage: she moves easily and effortlessly between her character's poignant observations from her prison cell and her own descriptions of the present-day process by which she came to appreciate Luxemburg's accomplishments and their lasting impact--an appreciation we all share by the end of the evening. Blue Rider Theatre, 1822 S. Halsted, 733-4668. Through February 26: Fridays-Saturdays, 8 PM; Sundays, 7 PM. $12.