The country's official language is Indonesian, a variant of Malay based on its prestige dialect, which had been the archipelago's ''lingua franca'' for centuries. It was promoted by nationalists in the 1920s and achieved official status under the name ''Bahasa Indonesia'' in 1945. As a result of centuries-long contact with other languages, it is rich in local and foreign influences, including Javanese, Sundanese, Minangkabau, Makassarese, Hindustani, Sanskrit, Tamil, Chinese, Arabic, Dutch, Portuguese and English. Nearly every Indonesian speaks the language due to its widespread use in education, academics, communications, business, politics, and mass media. Most Indonesians also speak at least one of more than 700 local languages, often as their first language. Most belong to the Austronesian language family, while over 270 Papuan languages are spoken in eastern Indonesia. Of these, Javanese is the most widely spoken and has co-official status in the Special Region of Yogyakarta.