The concept of "culture" has changed radically over time, broadening from a humanist idea of "the best in thought and speech" to an anthropological concept ton a concept that includes "tthe whole complex of distinctive spiritual, material, intellectual and emotional features that characterize a society or social group". UNESCO's program has over more than six decades expanded from one of diffusion of the "best of thought and speech" to include efforts to protect the diversity of cultural expression and to protect endangered languages.