The language and its status
Aragonés is the native language of Aragón, an autonomous community in northwest Spain. It belongs to the central branch of the north Ibero-Romance languages, making it an immediate sister of Castilian (Spanish), Asturian, and Ladino. It is closer to Spanish than is Portuguese (undoubtedly the closest to Spanish of the major Romance languages). The language is known variously as Aragonés, Alto Aragonés ("High Aragonese"), and Fabla Aragonesa ("Aragonese speech"). Aragonés, like Asturian, is close enough to Spanish to occasionally be referred to as a dialect, although in actuality it evolved in parallel with Spanish and is not fully mutually intelligible.
Complicating matters is the sheer linguistic plurality of the region. The language is often confused with the dialect of Spanish also known as Aragonés, which is influenced by the language. In addition, Aragón is home to a large number of Catalan speakers, borders on Occitania, and is a stone's throw from Basque country. This conflux of languages has resulted in a great deal of blurriness between them, and the region itself is officially trilingual, with Castilian, Catalan, and Aragonese all treated as official languages.
Aragonese, however, is very near extinction (some proponents, known as aragonesistas, claim it's Europe's most endangered language.) It is preserved by around 11,000 native speakers in isolated valleys in the Pyrenees and indeed only 500 or so monolingual speakers are still alive, all elderly. It is indeed in a precarious situation, with practically no media presence (a few radio broadcasts, some magazines and newspapers with Aragonese sections, and no television broadcasts at all). In addition, it is taught only occasionally in schools because competent teachers and textbooks are almost non-existent.
Some history
The language itself is somewhat transitional to Catalan, being closely related to Spanish but having significant Catalan influence. It bears as well an obvious resemblance to Asturian, indicating that both languages likely had a much greater domain at some point, allowing them direct contact for some part of history. At one point, coinciding with Aragón's period of political importance during the Middle Ages, Aragonés was a significant language.
In fact, it held sway over Catalonia and was one of the two important political bodies in Spain until the marriage of Ferdinand II (of Aragón) and Isabella I (of Castile) in 1461. This resulted in the merging of the two kingdoms and their territories, and eventually the complete unification of Spain. Castile attained linguistic dominance in Spain, resulting in the formerly regional language Castilian becoming the language of Spain's elite, and the decline of its other languages.
A tiny bit of linguistics
Aragonese is recognizable for its relation to Asturian, Castilian, Catalan, and Galego-Portuguese. Typical of Central North Ibero-Romance languages, it has a large number of diphthongs in stressed syllables, replacing the vowels /o/ and /e/ with /we/ ("ue") and /je/ ("ie") respectively. These sounds are highly recognizable as markers of the Central branch of the language group, being totally absent in the Western branch (i.e. Portuguese) and present in the Catalo-Occitan languages probably only due to contact with the Central Northern Ibero-Romance languages.
Another highly recognizable feature of the language is its stative verb, to be. As in Asturian, its second and third person singular are "yes" and "ye", with an initial /j/ sound not found in other Romance languages. It likely came about through contact with Asturianu. Another difference between Aragonese and Castilian is its preservation of some sounds lost in Castilian - the "sh" sound written with 'x' used, for example, in 'dixe', I said, which was replaced with 'j' in Castilian. Aragonese also preserves initial 'f' as in 'fillo', son ('hijo' in Castilian). Its phonology is on the whole much more conservative than Castilian.
Following is the Lord's Prayer in Aragonese:
Pai nuestro,
que yes en o zielo, satificato siga o tuyo nombre,
bienga ta nusatros o reino tuyo
y se faiga la tuya boluntá
en a tierra como en o zielo.
O pan nuestro de cada diya
da-lo-mos güei,
perdona las nuestras faltas
como tamién nusatros perdonamos
a os que mos faltan,
no mos dixes cayer en a tentazión
y libera-mos d'o mal.
Amén.