The music is rooted in Africa, but later adaptations of this and many other African folk idioms have permeated Western music (listen to Graceland by Paul Simon) and give modern South African music, particularly jazz, much of its distinctive sound and lilting swagger.
One reason for the use of the pennywhistle is that it is cheap and portable, but it also lends itself as a solo or an ensemble instrument. The popularity of the pennywhistle may have been based on the fact that flutes of different kinds have long been traditional instruments among the peoples of the more northerly parts of South Africa, and the pennywhistle thus enabled the swift adaptation of folk tunes into the new marabi-influenced music.
The word "kwela" is taken from the Zulu for "get up", though in township slang it also referred to the police vans, the "kwela-kwela". Thus it could be an invitation to join the dance, as well as serving as a warning. It is said that the young men who played the pennywhistle on street corners also acted as lookouts to warn those enjoying themselves in the shebeens of the arrival of the police.