Final answer:
In Spain, the language commonly spoken is often referred to as "español" or "castellano". The term used can depend on the region and local customs.
Step-by-step explanation:
Spanish speakers in Spain typically refer to the language they speak as "español", which is the Spanish word for Spanish. However, it's also sometimes referred to as "castellano", particularly in parts of Spain where other languages like Catalan, Galician, and Basque are spoken.
The term "castellano" stems from the Castile region in Spain, where the language was first spoken. The use of both terms varies and can depend on local customs and politics.
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