Insular Southeast Asia

Maritime Southeast Asia is the maritime region of Southeast Asia as opposed to mainland Southeast Asia and comprises Malaysia, Brunei, the Philippines, Singapore and Indonesia. Maritime Southeast Asia is sometimes also referred to as "island Southeast Asia" or "insular Southeast Asia". The 19th-century term "Malay Archipelago" refers to a largely similar area.

This main demographic difference that sets Maritime Southeast Asia apart from Indochina is that its population predominantly belongs to the Austronesian (Malayo-Polynesian, Melanesian and Micronesian) groups, although through trade with neighbouring groups from the Asian mainland like the Tai-Kadai, Austroasiatic, or Chinese, as well as other Oceanic groups like Papuans and Negritos there has been significant intermixing and cultural exchange.

The prevailing cultures of this region are maritime-based, tribal, and predominantly non-sinicized. Maritime Southeast Asia makes up the oldest bloc within Austronesia, with the Philippine archipelago representing the urheimat of all Malayo-Polynesians (non-Formosan Austronesians).

The cultural identity of the region is seen as both part of "Farther India" or Greater India, as seen in Coedes' Indianized States of Southeast Asia, which refers to it as "Island Southeast Asia"; and within Austronesia or Oceania, due to shared ethnolinguistic and historical origins of the latter groups (Micronesian and Polynesian groups) being from this region.

...
Wikipedia