The Chopi people of the coastal Inhambane Province are known for a unique kind of xylophone called mbila (pl: timbila) and the style of music played with it, which "is believed to be the most sophisticated method of composition yet found among preliterate peoples." Ensembles consist of around ten xylophones of four sizes and accompany ceremonial dances with long compositions called ngomi which consist of an overture and ten movements of different tempos and styles. The ensemble leader serves as poet, composer, conductor, and performer, creating a text, improvising a melody partially based on the features of the Chopi's tone language, and composing a second countrapuntal line. The musicians of the ensemble partially improvise their parts according to style, instrumental idiom, and the leader's indications. The composer then consults with the choreographer of the ceremony and adjustments are made. (Nettl 1956, p. 18-19)
Read more about this topic: Music Of Mozambique