vijayjohn wrote:Swahili is only a lingua franca in some parts of East Africa. Guarani is a lingua franca in and around Paraguay from what I understand (particularly on the border with Brazil), and e.g. Tukano is the lingua franca of the Vaupes R9ver Basin.
Quechua was once the lingua franca in parts of the Andes. The issue is that the indigenous languages have been replaced by Spanish as the lingua franca (and by Portuguese in Brazil). This makes it a rather different situation from Africa, where languages like Swahili are national languages. In South America I think only Guaraní comes close, but as Vijay mentioned, only in Paraguay. In Bolivia and Peru, Quechua and Aymara have official status, but so do several other indigenous languages, so they aren't necessarily used as lingua francas anymore, just spoken by their own populations.