A lingua franca (from Italian, literally meaning Frankish language, see etymology under Sabir and Italian) is a language systematically used to communicate between persons not sharing a mother tongue, in particular when it is a third language, distinct from both persons' mother tongues.
1839 - Trilingual Chinese-Malay-English text - Malay was the linga franca across the Strait of Malacca, including the coasts of the Malay Peninsula of Malaysia and the eastern coast of Sumatra in Indonesia, and has been established as a native language of part of western coastal Sarawak and West Kalimantan in Borneo.
Distribution of Arabic as sole official language (green) and one of several official or national languages (blue)
Hindustani, in its standardized registers, is the official language of both India (Hindi) and Pakistan (Urdu).
French dark blue: mother tongue
blue: official language
light blue: second language
green quarters: francophone minorities