In the extreme northeast of Portugal along the frontier south of Alcanices, between the bank of the river Angueira to the west and south, and the river Douro to the east, there is a cluster of villages where people use two languages to communicate with each other: Portuguese and Mirandese. Today, the two languages coexist in a situation of diglossia. While Portuguese is used in any sphere, the use of Mirandese is more restricted, being generally confined to the family or communication between villages.

Faced with this situation, a group of speakers, lecturers and language experts from Portuguese universities have worked together to come up with an orthographic convention for Mirandese. Bearing in mind that historically Mirandese belongs to the same family as ancient Leonese, the authors came up with an initial "Proposal…” (in 1995) that was publicly discussed. Some Spanish philologists and above all Asturian ones also contributed to this discussion. They sought and established united, systematic, clear and economic criteria, and that way they were able to come up with a common standardised written form for Mirandese.

To do this, a reduction in the graphical variation was sought as well as clarity in the graphical notation of certain phonological processes. The continuation of the graphical tradition was taken into consideration and an attempt was made to seek simplicity and flexibility. The result is a convention to facilitate written communication of Mirandese.