In contrast to traditional Arabic music, most Sudanese music styles are pentatonic, and the simultaneous beats of percussion or singing in polyrhythms are further prominent characteristics of Sudanese sub-Saharan music. The music of Sudan also has a strong tradition of lyrical expression that uses oblique metaphors, speaks about love, the history of a tribe or the beauty of the country. In his essay '"Sudanese Singing 1908–1958"', author El Sirr A. Gadour translated an example for the lyrics of a love song from the beginning of the 20th century as follows: