In some Romance languages (Spanish, Catalan, Italian, Portuguese), the progressive verbal periphrasis combines an auxiliary derived from Latin stare with a gerund (Spanish estar cantando). According to the morphosemantic theory in known as cognematics, those periphrases display a common submorphemic matrix st-nd which reveals the sense-making procedure shared by the homologous progressives in those languages. However, the way in which progressives are used in each language varies greatly on account of the systemic lexical and grammatical oppositions affecting the auxiliaries and the gerund. This study outlines the specificity of the Castilian progressive through the example of the verb acostumbrarse "to get used (to)".