Abstract: The Catalan secessionist parties, if added together, have won all the elections to the Parliament of Catalonia from 2010 to 2021. Their voters have been increasingly mobilized since the start of the controversial reform process of the Statute of Autonomy (2004–2010). The aim of this article is twofold. First, it intends to test whether language is the strongest predictor in preferring independence in two separate and distinct moments, 1996 and 2020. And second, to assess whether its strength has changed—and how—between both years. Only the most exogenous variables to the dependent variable are used in each of two logistic regressions to avoid problems of endogeneity: sex, age, size of town of residence, place of birth of the individual and of their parents, first language (L1), and educational level. Among them, L1 was—and still is—the most powerful predictor, although it is not entirely determinative. The secessionist movement not only gathers a plurality of Catalan native speakers, but it receives a not insignificant level of support among those who have Spanish as their L1. Conversely, the unionist group, despite being composed primarily by people who have Spanish as their L1 and have their family origins outside Catalonia, has a native Catalan-speaking minority inside. This imperfect division, which is based on ethnolinguistic alignments—and whose relevance cannot be neglected—alleviates the likelihood of an ethnic-based conflict.
Keywords: Catalonia; effective number of language groups; independence; language; logistic regression; secessionism; subjective national identity