The World Atlas of Language Structures (WALS) is a large database of structural (phonological, grammatical, lexical) properties of languages gathered from descriptive materials (such as reference grammars) by a team of authors.

PHOIBLE is a repository of cross-linguistic phonological inventory data, which have been extracted from source documents and tertiary databases and compiled into a single searchable convenience sample. Release 2.0 from 2019 includes 3020 inventories that contain 3183 segment types found in 2186 distinct languages.

Comprehensive reference information for the world's languages, especially the lesser known languages.