Why is Spanish called 'castellano' in Spain?

If you’ve ever taken language lessons, Spanish will of course be called Spanish. But when you arrive in Spain, you’ll find all the locals calling it castellano or Castilian instead.

So why is this? Why do Spaniards have a different name for their own language?

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Firstly, Spaniards are distinguishing castellano – what foreigners know as Spanish, from the other four official languages in Spain. These are Catalan, Basque, Galician and Valencian. There are also more minority languages and dialects such as Aragonese, Aranés and Leonés.

Secondly, it also differentiates between the Spanish spoken in Spain and the Spanish spoken in Latin America. Although they’re the same language, there are many differences in the vocabulary, grammar and of course accent.

Castellano or Spanish is the official language of the whole of Spain, but there are some other regions which have two official languages such as Catalonia, where Castilian and Catalan are used.

Castellano is named after the Kingdom of Castile, which predates the existence of modern Spain. The territory occupying a large part of northern half of Spain is where the language was first spoken.

It began as dialect spoken in this area and later became the language of the court of the kingdoms of Castile and León in the 12th century.

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Spain was not always one country with one official language, in fact it was made up of several different kingdoms. The unification of Spain began with the marriage of Ferdinand II of Aragón with Isabella I of Castile in 1496.

This united the two kingdoms of Aragón and Castile – the two largest territories in the Iberian peninsula.

At that time the Kingdom of Aragón included Catalonia, Mallorca, Valencia, Sicily and Sardinia, while the kingdom of Castile included Castile and León, Asturias, Galicia, Extremadura and then domains conquered from the Moors such as Córdoba, Murcia, Jaén and Seville.

Castilian wasn’t even close to being the majority language on the peninsula at this time, however. In Catalonia, Valencia, the Balearic Islands, Galicia, Asturias and the eastern half of Andalusia, it hadn’t even been heard of.

And only some people in León, Aragón, Navarre and the Basque Country knew it or were at least familiar with the Castilian language, as they were closer geographically.

Even the people who all spoken Castilian in different areas of the country found it difficult to understand each other because of the change in dialects and accents.

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In 1492, Antonio de Nebrija - the most influential lexicographer and grammarian of his time - completed a book called Grammar of the Castilian Language. This was the first publication that actually pulled the Castilian language all together and set out its rules.

This was also the year the same year in which the last Moorish stronghold of Granada fell to the crown. So, by this point, much of what we now know as Spain was coming together as one.

Nebrija was a friend of Queen Isabella I, and as Castilian was already the official language of the courts of Castile, he was able to influence her to promote the language across the parts of the country she ruled along with Spain's other Catholic Monarch, Ferdinand of Aragon. Over time, through various power struggles between merchants and other influential figures across the country, Castilian came out on top as the most dominant language.

It's important to remember, however, that it didn’t become the dominant language everywhere – Catalan and Valenciano still reigned in the east of the country – as it still does to this day – and Galician and Basque were still used more in the north and northwest of Spain.

This is why Castilian is often referred to as castellano in Spain. However, nobody will bat an eyelid if you refer to Spanish as español.

Even Spain's Royal Academy of Language (RAE) has ruled that español and castellano are synonyms, even though in Spain castellano is a more official way of referring to what is known as Spanish to foreigners.