Title: National language
Content:  Spain has one national constitutional language, Spanish or Castilian, but there are four other languages that are co-official in some territories: Galician language in Galicia, Basque in Euskadi and part of Navarre, Catalan language in Catalonia, Balearic Islands and Valencia (as Valencian), and Aranese in Val d'Aran.
Title: Languages of Spain
Content:  León and Zamora. In terms of the number of speakers and dominance, the most prominent of the languages of Spain is Spanish (Castilian), spoken by about 99% of Spaniards as a first or second language. According to a 2019 Pew Research survey, the most commonly spoken languages at home other than Spanish were Catalan in 8% of households, Valencian 4%, Galician 3% and Basque in 1% of homes. Distribution of the regional co-official languages in Spain: Spanish is official throughout the country; the rest of these languages have legal and co-official status in their respective communities and (except Aranese) are widespread enough to have daily newspapers and significant book publishing 
Title: Languages of Spain
Content:  The languages of Spain (lenguas de España), or Spanish languages (lenguas españolas), are the languages spoken in Spain. Most languages spoken in Spain belong to the Romance language family, of which Spanish is the only language which has official status for the whole country. Various other languages have co-official or recognised status in specific territories, and a number of unofficial languages and dialects are spoken in certain localities.
Title: Spaniards
Content:   Languages spoken in Spain include Spanish (castellano or español) (74%), Catalan (català, called valencià, in the Valencian Community) (17%), Galician (galego) (7%), and Basque (euskara) (2%). Other languages with a lower level of official recognition are Asturian (asturianu), Aranese Gascon (aranés), Aragonese (aragonés), and Leonese, each with their own various dialects. Spanish is the official state language, although the other languages are co-official in a number of autonomous communities. Peninsular Spanish is typically classified in northern and southern dialects; among the southern ones Andalusian Spanish is particularly important. The Canary Islands have a distinct dialect of Spanish which is close to Caribbean Spanish. The Spanish language 
Title: Official languages of Spain
Content:  Spanish (sometimes called Castilian) is the only official language of the entire country and is spoken habitually and as a native language among a vast majority of the Spanish population. Spain is, along with Colombia and after Mexico and the United States, ranked third in the world as the country with the most Spanish speakers. Spanish is the only official language in Asturias, Cantabria, La Rioja, Aragon, Castile and León, Madrid, Castilla-La Mancha, Extremadura, Andalusia, the Canary Islands and the region of Murcia, as well as Ceuta, Melilla, and half of Navarre. It is also co-official with other languages in Catalonia, Balearic Islands, Valencia, Galicia, Basque Country and the Basque zone of Navarre. In all of the bilingual autonomous communities, with the exception of 
Title: Official languages of Spain
Content:  native languages or languages that are not native but used, 98.9% of the population speaks Spanish, 17.5% speaks Catalan, 6.2% speaks Galician, 5.8% speaks Valencian (a variety of Catalan) and 3.0% speaks Basque. For autonomous communities, Catalan can be used by almost 85% of the population of Catalonia and 63.1% of the Balearic region, Galician is used by 89% of Galicians, Valencian is used by 51.8% of the residents in that community and Basque is spoken by 55.1% of the Basque population and 21.7% of people in Navarre. With regard to native languages alone, Galician is the native language of 82.8% of Galicians, Catalan is the native language of 31.6% of people 
Title: Languages of Spain
Content:  media presence. Catalan and Galician are the main languages used by the respective regional governments and local administrations. A number of citizens in these areas consider their regional language as their primary language and Spanish as secondary. In addition to these, there are a number of seriously endangered and recognised minority languages: Spanish itself also has distinct dialects. For example, the Andalusian or Canarian dialects, each with their own subvarieties, some of them being partially closer to the Spanish of the Americas, which they heavily influenced to varying degrees, depending on the region or period and according to different and non-homogeneous migrating or colonisation processes. Five very localised dialects are 
Title: Official languages of Spain
Content:  Catalonia and of 42.9% of the residents in the Balearic region. Valencian (a variety of Catalan) is the native language of 35.2% of the population in that community and Basque is the native language of 33.7% of the Basque people and of 14.6% of those from Navarre. With the exception of Basque, which is a language isolate, all of the vernacular languages spoken now in Spain are Romance languages, within the family of the Indo-European languages. The majority belong to the sub-group of languages Iberian Romance, with the exception of Catalan/Valencian and Aranes, belonging to the Occitano-Romances and Aragonese. Affiliation between one subgroup or the other is a cause for active discussion.
Title: Official languages of Spain
Content:  There is a variety of Vernacular languages spoken in Spain. Spanish, the official language in the entire country, is the predominant native language in almost all of the autonomous communities in Spain. Six of the seventeen autonomous communities in Spain have other co-official languages in addition to Spanish. Bilingualism in different degrees and in distinct communicative situations between Spanish and another language is a habitual practice for many of the Spanish people who reside in one of these autonomous communities. According to the Survey of the Involvement of the Adult Population in Learning Activities distributed by the National Institute of Statistics with data from 2016, in regards to the languages in Spain that 
Title: Languages of Spain
Content:  the border into Portugal. Mirandese is recognised and has some local official status. Portuguese has been traditionally spoken by the inhabitants of the following border areas: Cedillo and Herrera de Alcántara (province of Cáceres), La Alamedilla (province of Salamanca, primarily spoken in the place up until the mid-20th century), and Olivenza (province of Badajoz). With the exception of Basque, which appears to be a language isolate, all of the languages present in mainland Spain are Indo-European languages, specifically Romance languages. Afro-Asiatic languages, such as Arabic (including Ceuta Darija) or Berber (mainly Riffian), are spoken by the Muslim population of Ceuta and Melilla and by recent immigrants (mainly from Morocco) elsewhere.

Question: what are the four main languages spoken in spain?
Answer: Basque Language.