The Spanish language has two names: español (English: Spanish) and castellano (English: Castilian). Spanish speakers from different countries or backgrounds can show a preference for one term or the other, or use them indiscriminately, but political issues or common usage might lead speakers to prefer one term over the other. This article identifies the differences between those terms, the countries or backgrounds that show a preference for one or the other, and the implications the choice of words might have for a native Spanish speaker.
Today, the national language of Spain – the official Spanish language – is Spanish (as opposed to the regional languages of Spain, such as Galician, Catalan, Asturleonese, and Basque). Generally speaking, both terms (español and castellano) can be used to refer to the Spanish language as a whole, with a preference for one over the other that depends on the context or the speaker's origin. Castellano (as well as Castilian in English) has another, more restricted, meaning, relating either to the old Romance language spoken in the Kingdom of Castile in the Middle Ages, predecessor of the modern Spanish language, or to some formal varieties of Spanish which are popularly imagined as related to the historical region of Castile, in central Spain.