Cross-border Multilingual Toponymy and its Representation in GIS: Regional Language in the Cartography of the Basque Country

Toponymy reflects the linguistic and cultural heritage of communities, offering insights into social, historical, and geographical phenomena. Its descriptive and nominative aspects help understand territorial marginalization and borders, which can divide culturally unified regions and create tensions between administrative boundaries and cultural ties. This study focuses on the western cross-border region between Spain and France, specifically in Euskal Herria [Basque Country], marked by multilingualism (Euskera [Basque language], French, Spanish). It analyzes the linguistic distribution of toponyms, their origins, and cartographic treatment using a corpus from institutional and community sources, including OpenStreetMap (OSM). Results show a predominance of Euskera, with differences between urban and rural areas. Analysis by source reveals that OSM follows a linguistic pattern different from Spanish official bodies, while aligning with France’s approach. Overall, the proportion of Euskera in the Spanish region (HEH) is 83.7%, compared to 60% in the French region (IEH), regarding place names. The study also highlights differences between the current language of use and the functional language in place name formation, along with the influence of sociolinguistic policies on their graphic representation. It concludes by proposing the use of the common regional language in local productions and a global lingua franca for international communication. This methodology is applicable to other multilingual regions.