Origins

As a member of the Romance linguistic family, Spanish derived from Latin. The language is also called Castellano, mostly within Spain, as it was first the language of the Kingdom of Castille. Deriving from vulgar Latin, Spanish developed under the influence of Basque, locally spoken at that time. Like Portuguese, in a vast period of its history the state and language suffered the impact of Arabic. Today, Spanish is transformed into a language with many variations due to its large geographic distribution.

Official Language

Spanish is the official language of Spain, though within Spain it’s often called Castellano, or Castillian, in order to avoid confusion with Basque, Catalan and other locally spoken languages. It’s also official in almost all of South America, and in countries on all five continents, the total number of which is about 25. Spanish is an official language of the EU and one of the 6 official languages of the UN.
 
Varieties

Spanish has many varieties due to its vast geographical distribution. The standard language for Spain is the Madrid dialect, though there are significant variations even within the mother country. In South America, it varies from country to country and region to region, so they’re most often classified within national borders.

Brief History

The Latin Empire gave birth to all members of the Romance linguistic family. Latin was spread to new provinces by the army, so vulgar Latin was the base for all of the Romance languages’ future development. In each Romance language, the new tongue was gradually formed using both Latin and the local language. In the case of Spanish, Basque had a key influence in language formation.

Later on, the language became the official one for the growing Kingdom of Castille. It’s also called Castellano (Castillian) after the name of the Kingdom. In the branch of Iberian Romance, namely Spanish and Portuguese, another key factor can be detected. For several Centuries, Arabs dominated the peninsula and consequently influenced the language. Both Spanish and Portuguese adopted significant lexical content from Arabic, along with some minor amendments to the grammar.