Final answer:
Duke Ellington did indeed refer to his compositions as 'Negro folk music,' which is true. This reflects the cultural and musical heritage of African Americans that influenced his work.
Step-by-step explanation:
It is true that Duke Ellington sometimes referred to the music he composed as "Negro folk music." This terminology underscores the deep roots of Ellington's music in the African American experience and its cultural expressions. His work can be seen as an extension of the musical traditions that evolved from the experiences of the black community, including work songs, spirituals, blues, and jazz.
These genres reflected the highs and lows of life in predominantly black neighborhoods. No single person invented these styles; however, they amalgamated through shared experiences and expressions of the African American diaspora. Ellington's compositions represented a sophisticated synthesis of these traditions and contributed to America's rich musical tapestry.