|Spain (in the autonomous communities of Asturias, northwestern Castile and León and western Cantabria) and small border areas in northeastern Portugal.|
- Asturian, asturianu or bable, encompassing the vernaculars spoken in the Spanish province of Asturias, except the westernmost ones, which are more often considered dialects of Galician (see Eonavian below). This is the area with more speakers left.
- Leonese, llionés, encompassing the vernaculars spoken in northern and western parts of the province of León, and a few western areas in the provinces of Zamora and Salamanca, in Spain. The distinction between Asturian and Leonese cannot be made in purely linguistic terms. Leonese was spoken in the past in a much larger area; however, it is now approaching extinction.
- The now-extinct dialects of the neighbour parishes of Rio de Onor and Guadramil, in the northern border of the District of Bragança, in Portugal;
- Mirandese, mirandés, in villages around the border town of Miranda do Douro, in the eastern border of the District of Bragança, in Portugal.
- Astur-Leonese dialects closer to Spanish are spoken in Cantabria. Some of them, especially western ones, are further grouped with the traditional name montañés; some others are outside this group and use their local glotonims (namely, pasiegu). There are different positions about whether these varieties are dialects of the Spanish language, dialects of Astur-Leonese or independent languages on their own right.
- The Extremaduran language, estremeñu, spoken in northwestern Extremadura (Spain) is more distantly related to the group.
- The Asturian Eonavian dialect, eonaviegu or gallego-asturianu, spoken between the Eo and Navia rivers in Asturias is closer to Galician; it is sometimes considered the westernmost variety of Asturian, but it is more often seen as either a group of Galician dialects or an independent language.
Leonese (as a denomination for the whole linguistic group) was once regarded as an informal dialect (basilect) of Spanish or Castilian, but in 1906, Ramón Menéndez Pidal showed it was the result of Latin evolution in the Kingdom of León.
Leonese is officially recognised by the Autonomous Community of Castile and León (2006). In Asturias it is protected under the Autonomous Statute legislation and is an optional language at schools, where it is widely studied.
In Portugal, the related Mirandese language is recognized by the Assembly of the Republic as a co-official language along with Portuguese for local matters, and it is taught in public schools in the areas where Mirandese is natively spoken. Initially thought to be a basilect of Portuguese, José Leite de Vasconcelos studied Mirandese and concluded it was a separate language from Portuguese.
The language developed from Vulgar Latin with contributions from the pre-Roman languages which were spoken in the territory of the Astures, an ancient tribe of the Iberian peninsula. Castilian Spanish came to the area later in the 14th century when the central administration sent emissaries and functionaries to occupy political and ecclesiastical offices.
Much effort has been made since 1974 to protect and promote Asturian. In 1981 Asturian, or Bable, as the language is officially named, was recognized as an area in need of special protection by the local government. In 1994 there were 100,000 first language speakers and 450,000 second language speakers able to speak or understand Asturian. However, the outlook for Asturian remains critical, with a large decline in the number of speakers in the last 100 years. At the end of the 20th century, the Academia de la Llingua Asturiana underwent initiatives designed to provide the language with most of the tools needed to survive in the modern era: a grammar, a dictionary and periodicals. A new generation of Asturian writers has championed the language. These developments have given Asturian greater hope of survival.
Leonese was probably spoken in a much larger area in the Middle Ages, roughly corresponding to the old Kingdom of León. As the Spanish language became the main language in Spain, the linguistic features of the Leonese language retreated progressively westwards.
In the late 1990s several associations unofficially promoted Leonese language courses. In 2001 the Universidad de León (University of León) created a course for Leonese teachers, and local and provincial governments developed Leonese language courses for adults. Nowadays Leonese can be studied in the largest towns of León, Zamora and Salamanca provinces.
Leonese's desperate reality as a minority language has driven it to an apparent dead end, and it is considered a Seriously Endangered Language by UNESCO. There are some efforts at language revival aimed at the urban population (the Leonese Council has made campaign to encourage young people to learn Leonese). Some experts think Leonese will be dead in two generations.
In spite of all these difficulties, the number of young people learning and using Leonese (mainly as a written language) has increased substantially in recent years. The Leonese City Council promotes Leonese language courses for adults. Leonese is taught in sixteen schools in Leon.
In the 19th century, José Leite de Vasconcelos described Mirandese as "the language of the farms, work, home, and love between the Mirandese," noting that it was a completely separate language from Portuguese. Since 1986/1987 the language has been taught to students between the age of 10 and 11, and Mirandese is now recovering. Today Mirandese has fewer than 5,000 speakers (but the figure go up to 15,000 if one includes second language speakers).
Portugal has taken a further step in protecting Mirandese when the Portuguese Republic officially recognised the language in 1999. It is administrated by the Anstituto de la Lhéngua Mirandesa.
- "El dialecto leonés y el Atlas lingüístico de Castilla y León". Retrieved 2013-05-04. (Spanish)
- Maia, Clarinda de Azevedo (1996-10-01). "Mirandés". In Alvar, Manuel. Manual de dialectología hispánica. El Español de España [Spanish Dialectology Manual. Spanish from Spain] (in Spanish). Barcelona: Editorial Ariel, S.A. "En la provincia de Tras-os-Montes . . . aparte del habla trasmontana (con sus diferentes variantes) existen algunos dialectos estructuralmente próximos a los dialectos leoneses . . . La zona oriental de esta provincia portuguesa, que linda con tierras leonesas de Zamora, aparte de algunas modalidades regionales marcadamente individualizadas presenta algunos dialectos caracterizados, en diferente grado, por soluciones de tipo leonés. Estos dialectos parecen constituir dos núcleos distintos, no solo de acuerdo con su posición geográfica, sino, sobre todo, en virtud de los diferentes grados de predominio del leonesismo que presentan: por un lado, el grupo formado por los dialectos del rincón nordeste de la provincia, especialmente el de Rio de Onor y Guadramil, a los que se asocian, ya muy diluidos, los dialectos de otras dos poblaciones de la raya: Petisqueira y Deilão; por otro, en la zona oriental, hablado en la Terra de Miranda, el mirandés, el mas marcadamente leonés de todos los dialectos de factura leonesa hablados en territorio portugués, en el que conviene enmarcar como dialecto suyo, el sendinés, hablado en la población de Sendim . . ."
- Menéndez Pidal 1906:128-141
- UNESCO Interactive Atlas of the World’s Languages in Danger.[dead link]
- Ethnologue report for Spain.
- Euromosaic report, Lexikon der romanitischen Linguistik 6.I:652-708
- Bauske 1995
- [dead link]
- Llera Ramo 1994
- "Art. 5/2. Statute of Autonomy of Castile and León". February 10, 2010. Retrieved February 10, 2010.
- (German) (Spanish) Bauske, Bernd (1995) Sprachplannung des Asturianischen. Die Normierung und Normalisierung einer romanischen Kleinsprache in Spannungsfeld von Linguistik, Literatur und Politic. Berlin, Köster (There's also a Spanish translation: (1998) Planificación lingüística del asturiano. Xixón, Vtp ISBN 84-89880-20-4)
- (German) (Spanish) Lexikon der Romanitischen Linguistik, Bd. 6.I: Aragonesisch/Navarresisch, Spanisch, Asturianisch/Leonesisch. Tübingen, Max Niemeyer, ISBN 3-484-50250-9.
- (Spanish) Llera Ramo, F. (1994) Los Asturianos y la lengua Asturiana: Estudio Sociolingüístico para Asturias - 1991. Oviedo: Consejería de
Educación y Cultura del Principado de Asturias ISBN 84-7847-297-5.
- (Spanish) Menéndez Pidal, R (1906): "El dialecto Leonés", Revista de Archivos, Bibliotecas y Museos 2-3:128-172, 4-5:294-311 (There's a modern reprint: (2006) El dialecto Leonés. León, El Buho Viajero ISBN 84-933781-6-X)
- Wurm, Stephen A. (ed) (2001) Atlas of the World's Languages in Danger of Disappearing. UNESCO ISBN 92-3-103798-6.
- Héctor García Gil. Asturian-leonese: Linguistic, Sociolinguistic and Legal Aspects.
- Academia de la Llingua Asturiana – Academy of the Asturian Language – Official website
- Asturian grammar in English
- Xunta pola Defensa de la Llingua Asturiana – Committee for the Defense of Asturian Language
- Oficina de Política Llingüística del Gobiernu del Principáu d'Asturies – Bureau of Asturian Linguistic Politics (Government of the Principality of Asturias)
- Real Instituto de Estudios Asturianos – Royal Institute of Asturian Studies (RIDEA or IDEA), founded 1945.
- Asturian–English dictionary
- Entry on José Leite de Vasconcelos at the Folclore Português website
-  - González i Planas, Francesc. Institutum Studiorum Romanicorum «Romania Minor». The Asturleonese Dialects.
- La Caleya - Cultural Association.
- Furmientu Cultural Association.
- Faceira Cultural Association.
- El Teixu Cultural Association.