In these countries and territories, Spanish is the main or only language of communication of the vast majority of the population; official documents are written chiefly or solely in that language; and it is taught in schools and utilized as the primary medium of instruction as part of the official curriculum.
a In Spain, Spanish is the sole official language at the national level, while the languages of Basque, Catalan/Valencian, and Galician are co-official alongside Spanish in certain sub-national regions.