Leonese is a set of vernacular Romance language varieties currently spoken in northern and western portions of the historical region of León in Spain and a few adjoining areas in Portugal, where it is known as Mirandese, sometimes considered another language. In the past, it was spoken in a wider area, including most of the historical region of Leon. The current number of Leonese speakers is estimated at 20,000 to 50,000.

Asturian is a West Iberian Romance language spoken in the Principality of Asturias, Spain. Asturian is part of a wider linguistic group, the Asturleonese languages. The number of speakers is estimated at 100,000 (native) and 450,000. The dialects of the Astur-Leonese language family are traditionally classified in three groups: Western, Central, and Eastern. For historical and demographic reasons, the standard is based on Central Asturian. Asturian has a distinct grammar, dictionary, and orthography. It is regulated by the Academy of the Asturian Language. Although it is not an official language of Spain it is protected under the Statute of Autonomy of Asturias and is an elective language in schools. For much of its history, the language has been ignored or "subjected to repeated challenges to its status as a language variety" due to its lack of official status.