Explaining the forces underpinning grammaticalization paths: The progressive-to-imperfective shift in three varieties of Spanish

We provide an account of the synchronic variation between the use of the Simple Present marker [Verb-a] and the Present Progressive marker [estar + Verb-ndo] in the expression of the habitual reading in Modern Spanish. Results from an acceptability judgment task in three distinct dialectal varieties (Rioplatense Spanish, Iberian Spanish, and Mexican Altiplano Spanish) show: (a) the presence of variation across dialects, (b) that this variation is constrained by a grammaticalization path, the Progressive-to-Imperfective shift, and (c) that a generalization process is already underway in all three different dialects but at different degrees of progress: more conservative in the Rioplatense and Iberian varieties, and less so in the Mexican Altiplano one. Specifically, our results show that whereas the Simple Present is the preferred form to express the habitual reading, the Present Progressive marker is already available to convey this reading in the three dialectal varieties. However, in Rioplatense Spanish and Iberian Spanish, this use is restricted to contexts that independently satisfy the presuppositional content of estar – the auxiliary in the Present Progressive periphrasis [estar + Verb-ndo] –, which requires the existence of alternative situations at which the prejacent does not hold. This restriction appears to be eroding in Mexican Altiplano Spanish, which is manifested as a loss in the context-dependence of the Present Progressive marker