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 more than 40 authors
(many of them the leading authorities
on the subject).
WALS consists of 141 maps with accompanying
texts on diverse features (such as vowel inventory
size, noun-genitive order, passive constructions, and "hand"/"arm" polysemy),
each of which is the responsibility of a single author (or team of authors).
Each map shows between 120 and 1370 languages, each language being represented by a
symbol, and different symbols showing different values of the feature.
Altogether 2,650 languages are shown on the maps, and more than 58,000
datapoints give information on features in particular languages.
WALS thus makes information on the structural diversity of the world's
languages available to a large audience, including interested nonlinguists as well
as linguists who would not normally read grammars of exotic languages or specialized
works by comparative linguists. Although endangered languages are not particularly
emphasized, they are automatically foregrounded because of the large sample of
languages represented on each map, where each language (independently of its number
of speakers) is shown by a single symbol.