1) A language used as vernacular for communication amongst many speakers of different languages, i.e. a creole.
2) An early version of this, a mix of English, Spanish, Portuguese, Arabic and other languages with Italian.
3) (British) The English variant used by many Asian immigrants, mixing English with Indian tongues like Gujarati, Urdu/Hindi, Sinhalese, etc.
1) Swahili is the lingua franca in East Africa. Millions of people who speak indigenous languages also speak it for communication.