Every five years, the Tripartite Pact between the Government of Navarra, the Basque Government and the Public Institution of the Basque Country of Iparralde conducts a socio-linguistic survey of the Basque Country. It was last held in 2021 and results have been published this year.

In the case of Álava, Bizkaia and Gipuzkoa, 36.2% of the population older than 16 years is Basque, 18.6% is Vasco-speaking and 45.3% is Castilian speaking. Since the first survey in 1991, the number of Euskaldunes has increased by 12%. By region, more than half of the residents in Gipuzkoa (51.1 per cent) are Basque, one third in Bizkaia (30.6 per cent) and almost a quarter in Álava (22.3 per cent). By age, the highest percentage of Euskaldunes is among young people between 16 and 24 years old: 74.5% are Basque, compared to 25% in 1991. On the contrary, only 31.5% of those over 65 are Basque. The ones that are easier to speak in Spanish are 44.3%, 6.5% more than 30 years ago. Meanwhile, those who speak more easily in Basque are 27.4%, 7.2% less than in 1991.

In Nafarroa Garaia, 14.1% are Basque, 10.6% are Basque speakers and 75.3% are Castilian speakers. Since 1991, the number of people with Basque knowledge has increased by 10.6 per cent. In that year, the ratio to Basque receivers was double, with 60 per cent currently Basque and 40 per cent receiving. As for the age groups, the largest age group of those who know Euskera is young people from 16 to 24 years old, as 40% know it. On the contrary, only 15.7% of those over 65 are able to communicate in Basque. According to the areas defined in the Basque Law of 1986, 76% of the population of the Basque Country knows Basque, 24.1% of the current mixed area and 9.1% of the non-Basque area. According to the survey data, 51.6% of Basque speakers are bilingual Castilian, that is, they speak better in Spanish than in Basque. In both cases, 28% do it similarly and only 20.4% do it better or more easily in Basque. In the first year of the survey, the percentage of Castilian bilinguals was 32.8% compared to 40.6% of Basque bilinguals.

In the Northern Basque Country, Basques account for 20.1% of the total population, 9.4% of the receivers and 70.5% of the Castellanoparlantes. Compared to the 2011 results, the number of people with knowledge of the language has decreased by 1.2%, in line with the decline of previous years, but blurred. Among older people (+65) is the highest percentage of Euskaldunes, with 25.7%; among younger people (16-24 years) the proportion is 21.5% and has increased by 3.9% since 2011. As for the countries, almost half of the population of Baja Navarra and Zuberoa is Euskaldun, and without taking into account the BAM area (Baiona-Biarritz), the Basques are 23% in Lapurdi. In the case of the BAM field, only 8.4% know Euskera. Among the Vasco-speakers of Iparralde, the number of Euskaldunes that best develop in Basque continues to decline, although between 16 and 24 years it has begun to recover.