Spanish or Castilian (castellano) is a Romance language of the Indo-European language family that evolved from the Vulgar Latin spoken on the Iberian Peninsula of Europe. Today, it is a global language with about 500 million native speakers, mainly in the Americas and Spain, and about 600 million when including second language speakers. Spanish is the official language of 20 countries, as well as one of the six official languages of the United Nations. Spanish is the world's second-most spoken native language after Mandarin Chinese; the world's fourth-most spoken language overall after English, Mandarin Chinese, and Hindustani (Hindi-Urdu); and the world's most widely spoken Romance language. The country with the largest population of native speakers is Mexico.

Spain, or the Kingdom of Spain, is a country located in Southwestern Europe, with parts of its territory in the Atlantic Ocean, the Mediterranean Sea and Africa. It is the largest country in Southern Europe and the fourth-most populous European Union member state. Spanning across the majority of the Iberian Peninsula, its territory also includes the Canary Islands in the Atlantic Ocean, the Balearic Islands in the Mediterranean Sea, and the autonomous cities of Ceuta and Melilla in Africa. Peninsular Spain is bordered to the north by France, Andorra, and the Bay of Biscay; to the east and south by the Mediterranean Sea and Gibraltar; and to the west by Portugal and the Atlantic Ocean. Spain's capital and largest city is Madrid, and other major urban areas include Barcelona, Valencia, Zaragoza, Seville, Málaga, Murcia, Palma de Mallorca, Las Palmas de Gran Canaria, and Bilbao.