The Austronesians are represented in Việt Nam by
the Chamic speakers. These languages have undergone extreme
restructuring under the influence of Austroasiatic and they were not
immediately recognised as AustronesianThe exact period of Austronesian
incursions into Việt Nam cannot be dated, but it was
presumably before 0 AD, to account for the rise of the
Champa kingdom, which dominated this region in the
early medieval period and may represent the first written
examples of an Austronesian language
The Aceh of Sumatra are thought to
represent a remigration of Chamic back into
the Austronesian-speaking area, while Tsat, on Hainan island into the Sinitic
area. The founders of the Utsat community probably
fled to Hainan after break-up of the Cham Empire.