continuity consisting of the variant of Galician referred to as galego-português baixo-limiao, which is spoken in several Galician and Portuguese villages within the transboundary biosphere reserve of Gerês-Xurés. It is "considered a rarity, a living vestige of the medieval language that ranged from Cantabria to Mondego [...]". As reported by UNESCO, due to the pressure of Spanish on the standard official version of Galician and centuries-old Hispanization, the Galician language was on the verge of disappearing. According to the UNESCO philologist Tapani Salminen, the proximity to Portuguese protects Galician. The core vocabulary and grammar of Galician are noticeably closer to Portuguese than to those of Spanish and within the EU context, Galician is often considered the same language as Portuguese. Galician like Portuguese, uses the future subjunctive, the personal infinitive, and the synthetic pluperfect. Mutual intelligibility estimated at 85% is excellent between Galicians and Portuguese. Despite political efforts in Spain to define them as separate languages, many linguists consider Galician to be a co-dialect of the Portuguese language with regional variations. Another member of the Galician-Portuguese group, most commonly thought of as a Galician dialect, is spoken in the Eonavian region in a western strip in Asturias and the westernmost parts of the provinces of León and Zamora, along the frontier with Galicia, between the Eo and Navia rivers (or more exactly Eo and Frexulfe rivers). It is called eonaviego or gallego-asturiano by its speakers. The Fala language, known by its speakers as xalimés, mañegu, a fala de Xálima and chapurráu and in Portuguese as a fala de Xálima, a fala da Estremadura, o galego da Estremadura, valego or galaico-estremenho, is another descendant of Galician-Portuguese, spoken by a small number of people in the Spanish towns of Valverde del Fresno (Valverdi du Fresnu), Eljas (As Ellas) and San Martín de Trevejo (Sa Martín de Trevellu) in the autonomous community of Extremadura, near the border with Portugal. There are a number of other places in Spain in which the native language of the common people is a descendant of the Galician-Portuguese group, such as La Alamedilla, Cedillo (Cedilho), Herrera de Alcántara (Ferreira d'Alcântara) and Olivenza (Olivença), but in these municipalities, what is spoken is actually Portuguese, not disputed as such in the mainstream. The diversity of dialects of the Portuguese language is known since the time of medieval Portuguese-Galician language when it coexisted with the Lusitanian-Mozarabic dialect, spoken in the south