sentences:  After many years as a local chapter, Pi Delta Phi reorganized and declared itself the National French Honor Society in 1920, and later chartered the Beta Chapter at the University of Southern California in 1925, and the Gamma Chapter at the University of California, Los Angeles, in 1926.The society expanded slowly during the next fifteen years but enjoyed renewed interest after World War II.In 1949 the American Association of Teachers of French (AATF) endorsed the Society officially as the only collegiate French honor society in the United States.