Linguists have a variety of grim-sounding terms for languages with few or no native speakers.
Language revival and language revitalization are attempts to preserve endangered languages, and in a way that is what this website project is all about. It is true that in the natural course of things, languages, like everything else, sometimes die. People choose, for a variety of valid social reasons, not to teach their children their own mother tongue. Amerindian languages were deliberately destroyed, particularly in North America. In the earlier days of European contact, Indians were separated from their linguistic kin and resettled hundreds of miles away with individuals from other tribes who couldn't understand each other.