This paper addresses the issue of rafforzamento fonosintattico (RF), phonosyntactic doubling, typical of a wide range of Italo-Romance dialects, and its relation to the phenomenon of mixed paradigms, also attested in a number of Italian varieties. After a discussion of the basic properties of RF, the article introduces mixed paradigms and proceeds to show how RF is used morphologically to signal important morphosyntactic contrasts, such as the difference between the 2nd and 3rd persons singular where a homonymous outcome of habes/habet > a is found. The paper thus intends to put forward another case of morphologization on the basis of the interesting — and endangered — phenomenon of mixed paradigms.