Glottolog contains data about language endangerment drawn (and merged) from various sources listed in config/aes_sources.ini.
Almost all information in the Catalogue of Endangered Languages (one of our sources) includes a citation of the original source which provided this data (e.g. journal article, book, personal communication, etc.). You can find citation information at the top of the "Language Information by Source" box on each language page; if you wish to reproduce data such as speaker numbers, you may cite the original source provided there.
Source data has been merged using the following mapping between the endangerment categories in the source databases, resulting in what we call the Agglomerated Endangerment Scale (AES):
| UNESCO | LES-ELCat | EGIDS | AES |
|---|---|---|---|
| safe | at risk |
|
Not endangered |
| vulnerable | vulnerable | 6b (Threatened) | 6b (Threatened) |
| definitely endangered |
|
7 (Shifting) | 7 (Shifting) |
| severely endangered | severely endangered | 8a (Moribund) | 8a (Moribund) |
| critically endangered | critically endangered | 8b (Nearly extinct) | 8b (Nearly extinct) |
| extinct |
|
|
10 (Extinct) |
Glottolog provides coordinates for nearly all language-level languoids. The coordinate often represents the geographical centre-point of the area where the speakers live, but may also indicate a historical location, the demographic centre-point or some other representative point. Like (variant) names and country locations (but unlike language division and classification), coordinates are attributes close to observation and are therefore not given with a specific source in Glottolog. However, it is expected that any source attributed to the language in Glottolog would indicate a location compatible with the coordinate given in Glottolog. The actual sources for the coordinates in Glottolog are varied and include both individual points submitted by various users and ourselves as well as databases such as WALS, ASJP and human reading of Ethnologue maps. As such the coordinates in Glottolog are not a substitute for a full and well-founded source in language locations (or variant names). For that, one needs to look at the individual sources attributed to the language in Glottolog.