The official language of spain is Castilian (Castellano) and this is understood by the majority of Spaniards and is the language learnt by most visitors to the country, but most regions have alternative regional languages of their own.

In the coastal resorts of Spain, where most foreign visitors are destined for it is not entirely necessary to learn Spanish if you speak English as most people that you are likely to encounter will already have a reasonable grasp of English.  However it is much appreciated even in these areas if you attempt to make some effort to speak the language.

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Whilst Castilian Spanish is spoken in 44 countries around the world and by approximately 350 Million people, many regions of Spain also have their own officially recognised languages which are taught in schools and considered by many Spaniards to be there first language.  Catalan is the widest used of these with an estimated 10 million speakers, Galician Galego is spoken by an estimated 3 million people and is similar to Portuguese. Extremaduran and Asturian are other significant examples with native speakers in the 100,000's.  All of the Languages mentioned so far are related and are "romance languages" originating from latin.  The one exception to this is the Basque Language Euskera, this language is spoken by  approximately 700,000 people in the Basque regions of Northern Spain and Southern France.   Euskera is unrelated to any other language in Spain and its origins are completely unknown.