Although not unlike the marimba, the balafon is believed to have evolved entirely autonomously in West Africa. It is especially popular in Cameroon, Mali, and Guinea, though variants exist elsewhere.

The instrument can be either fixed or free standing, and the keys, which are struck with a rubber mallet, are fixed above a gourd to help produce the distinctive nasal resonance. Traditionally, the gourds were covered with spiders' egg sac filaments, but nowadays cigarette papers or plastic are more common. The fixed form of the instrument is generally laid on a flat surface, whilst the free standing one may be carried or strapped over the shoulder.

There is written evidence of the existence of the instrument dating back to at least the 12th century CE.

The etymology of the word is probably a combination of "bala", which is the name given to the instrument in the Mandinka language, with Europeans adding the suffix "phon" amended to "fon" relating to the Greek for speech or sound.

Recent renewed interest in world music has also led to a resurgence of performances and recordings of the Balafon, and its influence can be heard even in compositions which do not directly utilise it.

More Info: en.wikipedia.org