One of three barrier islands we visited with Exploritas, http://www.exploritas.org/
Most known in recent years as the home of descendents of African slaves who speak "gullah", described by http://coastalguide.com/gullah as "The Gullah language, a Creole blend of Elizabethan English and African languages, was born of necessity on Africa's slave coast, and developed in the slave communities of the isolated plantations of the coastal South. Even after the sea islands were freed in 1861, the Gullah speech flourished because access to the islands was by water only until the 1950's." Very few of the remaining descendants can speak it.
Read about Sapelo's fascinating history here: http://www.newgeorgiaencyclopedia.com/nge/Article.jsp?id=h-466&pid=p-44