In addition to listing linguistic materials (grammars, articles, dictionaries) describing individual languages, the database also contains the most up-to-date language affiliations based on the work of expert linguists.

[1][2] The creation of Glottolog was partly motivated by the lack of a comprehensive language bibliography, especially in Ethnologue.

External links are provided to ISO, Ethnologue and other online language databases The latest version is 5.0, released under the Creative Commons Attribution 4.0 International License in 2024.

It is part of the Cross-Linguistic Linked Data project hosted by the Max Planck Institute of Geoanthropology.

[4] Glottolog is more conservative in its classification than other databases in establishing membership of languages and families given its strict criteria for postulating larger groupings.