“Extinct” means there are no speakers left. The atlas includes presumably extinct languages since the 1950s.
When exactly is a language considered as endangered? As explained by UNESCO on the interactive altas’ website: “A language is endangered when its speakers cease to use it, use it in fewer and fewer domains, use fewer of its registers and speaking styles, and/or stop passing it on to the next generation. No single factor determines whether a language is endangered.”
UNESCO experts have identified nine factors that should be considered together: (1) intergenerational language transmission; (2) absolute number of speakers; (3) proportion of speakers within the total population; (4) shifts in domains of language use; (5) response to new domains and media; (6) availability of materials for language education and literacy; (7) governmental and institutional language attitudes and policies including official status and use; (8) community members’ attitudes towards their own language; (9) amount and quality of documentation.
What are the causes of language endangerment and disappearance? “A language disappears when its speakers disappear or when they shift to speaking another language -- most often, a larger language used by a more powerful group. Languages are threatened by external forces such as military, economic, religious, cultural or educational subjugation, or by internal forces such as a community’s negative attitude towards its own language. Today, increased migration and rapid urbanization often bring along the loss of traditional ways of life and a strong pressure to speak a dominant language that is -- or is perceived to be -- necessary for full civic participation and economic advancement.”
End of the Project Gutenberg EBook of The web, a multilingual encyclopedia, by Marie Lebert