The Typological Database System (TDS) is a collection of independently developed typological databases. Unified querying is supported with the help of an integrated ontology.

The component databases of the TDS are cross-linguistic databases used for research in language typology and linguistics. They add up to some 1200 different descriptive properties, about more than 1000 languages. Most of the data is in the form of high-level “analytical” properties, but there are also a few collections of example sentences (with glosses) illustrating particular phenomena.

TLA-team: The TDS contains a wide collection of linguistic features for a broad range of
languages. These features are in most cases fairly low level as they are imported
from and stay close to the original database schemas and entries created by
typologist. Due to this getting a quick overview of the linguistic diversity in the
languages of the world for a specific linguistic phenomena might require more effort
than needed in other typological systems, like WALS, where all of these details have
aggregated into a limited set of features with limited value ranges. However, for
typologist this level of detail will be an advantage.
As the TDS integrates various databases one needs to be aware that with a
combination of features one will in general get the intersection between the sets of
languages covered by these databases. This intersection will not be a balanced
sample of the languages of the world. This has to be taken into account when drawing
conclusions from data taken from the TDS.