http://purl.org/dc/terms/language

used by 17:

• agris
• bioimages
• chronicling-america
• ctic-public-dataset
• data-bnf-fr
• enel-open-data-dcat
• ghent-university-academic-bibliography
• gutenberg
• idreffr
• linked-open-ipa
• mexico
• open-library
• public-record-office-victoria-semantic-wiki
• stitch-rameau
• sudocfr
• taxonconcept-assets
• thesesfr