Analysis of information sources in references of the Wikipedia article "Ngôn ngữ bị đe dọa" in Vietnamese language version.
A language is said to be dead when no one speaks it any more. It may continue to have existence in a recorded form, of course traditionally in writing, more recently as part of a sound or video archive (and it does in a sense 'live on' in this way) but unless it has fluent speakers one would not talk of it as a 'living language'.
As a result, without professional guidance, figures in popular estimation see-sawed wildly, from several hundred to tens of thousands. It took some time for systematic surveys to be established. Ethnologue, the largest present-day survey, first attempted a world-wide review only in 1974, an edition containing 5,687 languages.
