Wade Davis is a National Geographic Explorer-in-Residence (an awesome-sounding job that I kinda want) and an anthropologist. He travels worldwide, living with indigenous people and documenting their cultures. In this TED Talk from 2003, Davis talks about endangered languages and endangered cultures -- cultures are being lost at an astounding rate (at least in 2003, one human language was going extinct every two weeks). Further, he shares his vision of the ethnosphere, "humanity's great legacy" of culture, and gives fascinating examples of how it's being lost in small pockets of dying culture around the world.

Representative quote: "every language is an Old-Growth Forest of the mind." If the talk is too heady, just tune out and watch the National Geographic photos.