Glottolog is a language information and bibliography resource developed as an initiative of the Max Planck Institute for Evolutionary Anthropology in Leipzig. Its 5.3 edition offers a comprehensive catalogue of the world’s languages, language families, and dialects, collectively described as “languoids.” Each languoid is assigned a unique, stable Glottocode, and entries are organized in a genealogical classification grounded in available historical-comparative research. The website also provides Languoids information and a glossary to help users understand its classifications and terminology.

Glottolog’s References section, also known as Langdoc, contains bibliographical data on descriptive works concerning the world’s lesser-known languages. Its collection includes more than 460,000 references to materials such as grammars, dictionaries, word lists, and texts. Users can search by author, year, title, country, and genealogical affiliation, or apply more complex filters, including document type and macro-area. Bibliographic records can be downloaded in several formats or accessed through the Zotero Firefox plugin.