Spanish (español) or Castilian (castellano) is an Iberian Romance language. It is the most-widely spoken Romance Language, and the fourth most-widely spoken language in the world according to some sources, while other sources list it as the second or third most spoken language. It is spoken by 332 million people where official language (1998 data) and 32 million where not (28 million in the US, 2000 data), current total speakers are more than 400 million.
Originating in Spain and whence it was later brought by Spanish explorers, colonists, and empire-builders to the Western Hemisphere and other parts of the world during the last five centuries, Spanish is one of the top five most spoken languages worldwide, and is one of the six official working languages of the United Nations.
Spanish is one of the official languages of the United Nations and the European Union. The majority of its speakers are confined to the Western Hemisphere, and Spain.

With approximately 106 million first-language and second-language speakers, Mexico boasts the largest population of Spanish-speakers in the world. The four next largest populations reside in Colombia (44 million), Spain (c. 40 million), Argentina (39 million) and the United States of America (U.S. residents age 5 and older who speak Spanish at home number 31 million).
Spanish is the official and most important language in 22 countries: Argentina, Bolivia (co-official Quechua and Aymara), Chile, Colombia, Costa Rica, Cuba, Dominican Republic, Ecuador, El Salvador, Equatorial Guinea (co-official French), Guatemala, Honduras, Mexico, Nicaragua, Panama, Paraguay (co-official Guaraní), Peru (co-official Quechua and Aymara), Puerto Rico (co-official English), Spain (co-official Catalan, Galician and Basque), Uruguay, Venezuela, and Western Sahara (co-official Arabic).

In the United States, Spanish is spoken by three-quarters of its 41.3 million Hispanic population. It is also being learned and spoken by a small, though slowly growing, proportion of its non-Hispanic population for its increasing use in business, commerce, and both domestic and international politics. Spanish does hold co-official status in the state of New Mexico, and in the unincorporated U.S. territory of Puerto Rico.