The Austronesian languages form one of the world's largest language families, spoken by approximately 328 million people across a vast area from Maritime Southeast Asia and the Pacific Ocean to Madagascar and Taiwan. With over 1,250 languages, it ranks as the fifth-largest family by number of speakers and the second-largest by the number of distinct languages. Major examples include Indonesian (spoken by around 252 million), Javanese, and Tagalog.

The geographical span of these "Southern Island languages"—a term coined by Wilhelm Schmidt—was the largest of any language family before the colonial era, stretching from Madagascar to Easter Island. While most primary branches of Austronesian are found exclusively among the indigenous peoples of Taiwan, all other Austronesian languages worldwide belong to the significant Malayo-Polynesian subgroup. The linguistic similarities were first noted by Dutch scholar Adriaan Reland in 1706, and the oldest known written attestation dates back to a Cham inscription from approximately 350 AD.