This paper falls within the line of research dealing with the role of intralinguistic variation in contact-induced language change. Two constructions are compared in terms of their respective degrees of grammaticalization: the progressive periphrasis ese lì c/a+Verb, which is widespread in some Northern Italo-Romance dialects, and the corresponding Italian construction essere lì che/a+Verb. The study focuses on the presence of such constructions in Turin, the capital of the north-western Italian region of Piedmont, in which the former periphrasis is less grammaticalized than the latter. It contends that the grammaticalization process of essere lì che/a+Verb was triggered by the contact between Piedmontese dialect and Italian, whereas the pace of grammaticalization of this periphrasis is affected by the contact between different varieties of Italian. The paper points out that the case study may provide insight into more general issues concerning not only the interplay of contact and variation in language change but also the role of sociolinguistic factors in shaping contact-induced grammaticalization phenomena.