Spanish also called Castilian is a Romance language that originated in the Castile region of Spain and today has hundreds of millions of native-speakers across the world.

Spanish is a part of the Ibero-Romance group of languages, which evolved from several dialects of Vulgar Latin in Iberia after the collapse of the Western Roman Empire in the 5th century. The oldest Latin texts which show traces of Spanish come from mid-northern Iberia in the 9th century, and the first systematic written use of the language happened in Toledo, then capital of the Kingdom of Castile, in the 13th century. Beginning in the early 16th century, Spanish was taken to the colonies of the Spanish Empire, most notably to the Americas, as well as territories in Africa, Oceania and the Philippines.

Spanish is one of the six official languages of the United Nations. It is also used as an official language by the European Union, the Organization of American States, and the Union of South American Nations, and by many other international organizations. It is the first language of 570 million people and the second language of 90 million.

There is a marked divergence of the Spanish spoken in Spain (Castillian) and that of Latin America. Other dialectical differences are found across Latin America due to the influence of Portuguese and English as well as Quechua and other Native American languages.