Nicholas Ostler's Empires of the Word is about widely-spoken languages, but Ostler is also the chairman of the Foundation for Endangered Languages. He mentions in Empires of the Word that “it is reasonable to believe that, for half the world's languages, their last speakers may already be alive today.”
I'm obsessed with how it feels to be the last speaker of a language -- a state perhaps as far removed as it's possible to get from having what literary agents call a “platform.” Here's an unbearably poignant statement I once found in an oral history --
“I am the last full-blood Chunut left. My children are part Spanish. I am the only one who knows the whole Chunut or Wowol language. When I am gone no one will have it. I have to be the last one. All my life I want back our good old home on Tulare Lake. But I guess I can never have it. I am a very old Chunut now and I guess I can never see the old days again. Now my daughter and her Mexican husband work in the cotton fields around Tulare and Waukena. Cotton, cotton, cotton, that is all that is left. Chunuts cannot live on cotton. They cannot sing their old songs and tell their old stories where there is nothing but cotton. My children feel foolish when I sing my songs. But I sing anyway:
Toke-uh lih-nun Wa-tin-hin nah yo
Hiyo-umne ahe oonook miuh-wah
That is all.”
-- Yoimut, 1933, from The Way we Lived: California Indian Reminiscences, Stories and Songs, copyright 1981.
Daniel Nettle's and Suzanne Romaine's Vanishing Voices: the Extinction of the World's Languages contains photographs of the last surviving speakers of Ubykh, Catawba Sioux, Wappo, Manx, Eyak, and Yahi. All wear somewhat haunted expressions, although of course, one can hardly conclude that they went around looking that way all the time...
“It's not that I worship language for its own sake. Nor do I want to preserve a lot of cultural-linguistic groups for my own (or my colleagues') pleasure of studying them. I'm concerned instead that humanity itself; the species H. Sapiens, may be at evolutionary risk. The wholesale disappearance of languages, and what I will argue is the consequent reduction of cultural diversity, may threaten our survival.” -- H. Russell Bernard, “Preserving language diversity" in "Human Organization" 51:82-89.