In 2017, Spain had roughly 46 million inhabitants. Castellano is the country's official national language and the most common one spoken by most citizens (it is the mother tongue of 64.1% of the nation's citizens). In Spain, the Spanish language is never legally referred to as español but always as castellano, that is, Castellano. But though in legal terms Spaniards speak Castellano, in everyday life the words Castellano and Spanish are synonymous. For them, Spanish is the language used in South America or elsewhere in the world. In all of Spain's legal documents, be they for the central government or for the autonomous communities, the only term used to name the country's official national language is castellano. When people use expressions like "lengua española" or "lenguas españolas" ("Spanish language" or "Spanish languages"), they mean one of the languages spoken in Spain. Simply put, all languages spoken in Spain (Castellano, Catalan, Basque et Galician) are Spanish languages. To summarize, the word Castellano refers to the common language of the entire Spanish state in relation to the other official languages, such as Catalan, Galician or Euskera (Basque) in their respective autonomous communities.

As a result, Spain isn't a linguistically homogeneous country. Other mother tongues are used by a significant portion of the population: Catalan (10 million, spoken as a native language by 4 million), Galician or Galego (2.3 million), Basque or Euskara (580,000), Tsigane (600,000), Asturien or Bable (200,000), Aragonian or Fabla (30,000), Aranian (3,814), etc. Apart from Basque, which is a separate linguistic phenomenon (Basque family of languages), these are all Romance languages of Indo-European origin, except Tsigane, which belongs to the Indo-Iranian branch of the Indo-European family. While speakers of Catalan, Galician and Basque live in just a few autonomous communities, only speakers of Castellano and Tsigane can be found right across the country. Still, those who speak Tsigane, Asturain and Aragonian are not as well protected legally.16 million Spaniards who speak a mother tongue other than Castellano can be found throughout the country's autonomous communities.

While speakers of Catalan, Galician and Basque live in just a few autonomous communities, only speakers of Castellano and Tsigane can be found right across the country. Still, those who speak Tsigane, Asturain and Aragonian are not as well protected legally. In all, close to 16 million people live in Spain's autonomous communities.

The legal status of languages differs at the central-government and autonomous-community levels in Spain. Again, Castellano is the "official national Spanish language" ("la lengua española oficial del Estado"), but three other languages—Catalan, Galician and Basque—have co-official status in certain autonomous communities, while still other languages have only limited protection or status. The statutory expression used to designate official languages other than Castellano is "language proper" ("lengua propria" or "lenguas proprias"); the concept or expression isn't common in English or French; still, while French would more commonly refer to a "regional or heritage language," English would most often use the terms "regional or native language." According to article 3 (three paragraphs) of the Spanish constitution, Catalan, Basque and Galician are recognized as co-official languages along with Castellano in the communities (regions) where these languages are spoken, but Castellano remains the only official national Spanish language:

Artículo 3

1. El castellano es la lengua española oficial del Estado. Todos los españoles tienen el deber de conocerla y el derecho a usarla.
2. Las demás lenguas españolas serán también oficiales en las respectivas Comunidades Autónomas de acuerdo con sus Estatutos.
3. La riqueza de las distintas modalidades lingüisticas de España es un patrimonio cultural que será objeto de especial respeto y protección.

Article 3

1. Castilian is the official Spanish language of the State. All Spaniards have the duty to know it and the right to use it.
2. The other Spanish languages shall also be official in the respective Autonomous Communities in accordance with their Statutes.
3. The wealth of the different language variations of Spain is a cultural heritage which shall be the object of special respect and protection.
    

Though all Spaniards have a duty to know Castellano, the same obligation doesn't apply to Catalan, Basque, Galician, etc. Using these minority languages in Spain is simply a right, not an obligation. The languages are thus official to different extents: Castellano stands as the entire nation's official language, and this status gives it definite predominance.

As for language rights, the Spanish constitution recognizes two types of citizen and two types of territory. Specifically, the constitution calls for a unilingual Spanish state comprising territories that are either officially unilingual (for Castilanophones) or officially bilingual (for Catalans, Basques, Galicians, Aranians, etc.). The Spanish state could have gone with another option, namely recognizing a constitutionally multilingual country (Spain) comprising unilingual territories (Catalonia, Valencia, Basque Country, Galicia, Balearic Islands, etc.). But that model was not adopted. In fact, the recognition afforded to Spain's various languages must not undermine the usage or prevalence of Castellano, the Spanish nation's official language. Certainly, this model of bilingualism differs tremendously from Canada's, where the federal government is bilingual and the provinces generally unilingual (French in Quebec, English elsewhere), except in New Brunswick and the territories (French-English bilingualism, plus Inuktitut and Inuinnaqtun in Nunavut).

Castellano is thus the only language recognized by the Spanish state for the entire country. In practice, that means only Castellano is used for the Cortès Generales (Madrid)—a parliament (assembly of elected members) and a senate—for administrative operations and related services, for the courts and legal system, for road signs (relevant to the State), for public notices, etc. Still, a certain plurilingualism is now practised by exception in the senate, the result of extensive political talks and often heated parliamentary debates.

The status of "co-official language" does not legally bind the Spanish state itself, only the local administrations, that is, the bilingual autonomous communities in question. Those places aside, Spain is in essence a unilingual country in which only Castellano has any official status in the nation's life (social, cultural, economic, political, military, etc.).

The only other languages used in any official capacity (publicly) are Catalan (in Catalonia, Valencia and the Balearic Islands), Basque (in Basque Country and Navarre) and Galician (in Galicia), all bilingual autonomous communities.

Though Castellano is Spain's only official national language, the country has worked out a number of compromises for Catalonia, Valencia, Basque Country and Galicia. Generally, the head of state (the king) speaks Castellano to the whole of the citizenry. However, he uses Catalan as a matter of principle when speaking officially in Catalonia. On the other hand, the country's central political assemblies (Cortès Generales) use nothing but Castellano, all other languages being prohibited, except in the senate, which admits the country's co-official languages. Since 1998, the official state newspaper (Diario Oficial) is published in other languages once its Castellano-language version is distributed.

Spain's constitutional court uses strictly Castellano, so neither Catalan nor any other co-official language of autonomous regions is accepted for appeals or submissions. The court even contends that, to be admissible for consideration, documents written in the co-official language of an autonomous community must be systematically translated into Castellano. In general, state courts or tribunals exercising on autonomous-community territories accept documents in Catalan, Basque or Galician if they include a translation—that is, when the documents come from the court that first heard the case in question

In a decree dated June 26, 1986, Spain's constitutional court—the equivalent of Canada's Supreme Court—ruled that "any peripheral government" (meaning "decentralized") of the Spanish state and all "courts of law" hearing cases in autonomous communities that have co-official language status must work within that system. As a result, citizens living in autonomous communities with more than one official language officially have the right to use any of these languages to access Spain's decentralized government services and all courts of law. This "right" has yet to appear in the Spanish constitution and so remains a simple edict of the country's highest court.

That's why Spain was compelled to adopt a law dealing both with the legal system of public administrations and with administrative proceedings (Bill 30, November 26, 1992). Article 36 says that Spain's national administration must use Castellano, but in autonomous communities with a co-official language, that language must also be recognized. In practice, that means authorities must not only respond in the language used by the individual but also provide documentation in that language. The principle driving this policy is that citizens' language rights take precedence over those of public servants in the country's various administrations. What's more, article 19 of Bill 30/1984 states that public servants who work in officially bilingual territories must have proper command of each language.

In reality, Spain's practices have stayed the same for two decades. Calls for applications in government positions include the textual requirement set out in article 19 but they neither impose nor request proof of linguistic proficiency as a way to effectively assess applicants' suitability. So, actual bilingualism among Spanish civil servants is still rare. For instance, up until 1998 in Catalonia, fewer than 10% of public-service positions required knowledge of Catalan; though the percentage has greatly increased, it still is a far cry from the 100% level required by law; that's why persons using languages other than Castellano in central-government administrative offices located in autonomous communities face clear discrimination and disadvantages.

Compared with Canada, Spain as a whole is a unilingual country, and only its autonomous communities (Catalonia, Valencia, Balearic Islands, Basque Country, Galicia and Navarre) practise bilingualism. In that sense, the well-worn motto among Spaniards "in Castellano at least" ("al menos en castellano" or "al menos en castellano, lengua española oficial del Estado") appears to contradict the principles of a system that calls for two official languages. As things stand, Spain's official languages aren't on a level playing field, because Castellano clearly has the upper hand. In Canada, the principle of official bilingualism and the right to any official language stands equally for ALL official languages, and not first and foremost for one language (Castellano) and then for others (Catalan, Basque, Galician). Unfortunately, language policies around the world all have shortcomings, and Spain's is no different: bilingualism is a strictly regional reality based on an asymmetrical equality that favours Castellano. Thus, it's not surprising to hear claims for policies to wrestle Spain's "Castellano unilingualism" to the ground. That Spain's 1978 constitution failed to enshrine any sort of legal status for the country's "other Spanish languages" (Basque, Catalan, Galician) in central or national institutions or agencies undermines these languages. The debate surrounding Spain's constitution has barely begun, and today one can hear talk of a "federal state" or "a plurinational state."

Despite obvious pitfalls, Spain's effort to have the national official language co-exist with the country's "other Spanish languages" represents one of the Western world's most ambitious interventions in this area, especially given the population involved (16 million citizens in autonomous communities) and, the Basque Country aside, given the relative harmony among language groups so far. In 2014, a survey indicated that only 55% of Spaniards have Castilian for their mother tongue. Let us not forget that linguistic minorities have at least 27 million speakers in Spain (out of a population of 46.6 million) and that there is relative harmony between the various linguistic groups, with the exception of the Basque Country. As such, Spain is one of the models that best represent the trend among nation-states toward recognizing cultural and regional identities without undermining the unitary character of the nation as a whole. This in itself is already a tremendous success.