The Marquesas is a group of ten “high islands,” volcanic islands characterized by tall, rugged mountains walled by steep cliffs. Almost all the Marqueses happen to be in the path of the South Equatorial Current, prevented coral reefs from forming as they have around most other Polynesian islands. This means that rather than lazy sandy beaches, Maquesan island coasts are dotted with sea caves and harsh surf.
Settlers first arrived in the Marquesas from Tonga and Samoa in approximately 100 A.D. and developed communities in the deep valleys between the mountains. Because of the inaccessibility of many of these valleys people on the Marquesas Islands had relatively less contact with both their immediate and also Eastern Polynesian neighbors than those on other islands. Even so, by the late 1800s Western sailors found them and, very unfortunately, so did diseases Westerners brought; the Marquesan population declined from an estimated 70,000 to 100,000 before Western contact all the way down to less than 2,000 in 1920. When the French annexed the islands in 1842 they replaced the traditional chiefs with French officials. French Catholic missionaries forbade Marquesan cultural practices like chanting and tatooing. The French established schools and taught lessons only in the French language. After World War II the French became interested in using the Marquesas as a testing ground for their nuclear weapons program, increasing their administrative and economic interest in the islands, and solidifying the dominance of French language and culture.
Today the Marqesans are rebuilding their population and trying to revive their culture, though the Marquesan language continues to struggle.
The Documentation of Endangered Language page about Marquesan not only describes the disappearance of the language, but as a bonus offers a few photos of the islands–they’re really quite striking.