Vitality is dependent on a whole host of factors which some of the references below will help you understand.
- For a stark look at the links between demography and vitality, check out the case histories of population decline and recovery on SIL's Electronic Working Papers page
- See Lewis & Simons' EGIDS table: EGIDS is a 13 level scale that indicates language vitality.
- IEV: Lynn Landweer's Indicators of Ethnolinguistic Vitality document During her 15 year tenure as a surveyor in Papua New Guinea, Lynn Landweer studied the sociohistorical,socio-cultural, sociolinguistic milieu of the country. One of the results of that period of study was a model assessing ethnolinguistic vitality now referred to as the Indicators of Ethnolinguistic Vitality. This is a collection of factors that have been useful in indicating the probable direction a speech community will go relative to the maintenance of, or shift from its traditional language. (pdf file @ 66KB)
- UNESCO Atlas of the World’s Languages in Danger UNESCO’s Atlas of the World’s Languages in Danger is intended to raise awareness about language endangerment and the need to safeguard the world’s linguistic diversity among policy-makers, speaker communities and the general public, and to be a tool to monitor the status of endangered languages and the trends in linguistic diversity at the global level. The online edition provides additional information on numbers of speakers, relevant policies and projects, sources, ISO codes and geographic coordinates. This free Internet-based version of the Atlas for the first time permits wide accessibility and allows for interactivity and timely updating of information, based on feedback provided by users.