This chapter undertakes an overview of the structural conditions regulating the distribution of a phonological fortition process, raddoppiamento fonosintattico “phonosyntactic doubling”, in the Calabrian dialect of Cosenza, focusing on some particularly striking cases which also reveal the role of phases in constraining the application of RF. On the one hand, the data highlight the advantages of interpreting locality not just narrowly in terms of the three core structural configurations Spec-Head, Head-Head and Head-Comp, but also more broadly in terms of phasal domains, showing how different phonological realizations represent the spell-out of deep syntactic differences mapped at the interface between narrow syntax and PF (Phonological Form). On the other, the theoretical assumptions assumed here provide us with the key to understanding some intriguing empirical generalizations about the role of RF in signalling, among other things, informational structure content and binding relations, which, in turn, throw new light on current theoretical assumptions about clause structure and the nature of phases.