http://www.endangeredlanguages.com/

Humanity today is facing a massive extinction: languages are disappearing at an unprecedented pace. And when that happens, a unique vision of the world is lost. With every language that dies we lose an enormous cultural heritage; the understanding of how humans relate to the world around us; scientific, medical and botanical knowledge; and most importantly, we lose the expression of communities’ humor, love and life. In short, we lose the testimony of centuries of life.