Does the server support searching/filtering by string literals' language tags?

[alexkreidler]

The RDF spec describes that each literal may have a language tag. For large datasets that include RDF property values in many languages, such as Wikidata (example LDF query), it could be very useful to filter by language tag to reduce the result size. As far as I can tell, the LDF spec does not make any reference to language tags.

Would this be a useful addition to this software/the specification?

[rubensworks]

The TPF spec already contains a piece on language tags on literals: https://linkeddatafragments.org/specification/triple-pattern-fragments/#controls
Using this, you can filter by literal+lang.

In another note, it looks like the Wikidata endpoint has a bug though, as it's not exposing language tags properly, and instead exposes literals through the rdf:langString datatype.