ABSTRACT
This chapter addresses the problem of the 'justification' for the existence of a supposed Adriatic-Tyrrhenian corridor. The difficulties in the relationship between the disciplines of dialectology and history become clear in the pages that the French historian Lucien Febvre devoted to the subject. The fact that metaphony of /a/ is triggered by both -i and -u may be significant for the categorization of the Phlegraean area as well as for understanding of the Adriatic—Tyrrhenian corridor. Historical information can help assign greater plausibility to one of the scenarios that may be outlined purely on the basis of the examination of linguistic structures and processes. It should also be noted that traces of spontaneous palatalization of non-metaphonic origin have been attested across the whole Phlegraean area, in different lexical categories. One characteristic of the Phlegraean area is that the process of metaphonic palatalization of /a/ is triggered by word-final -I and word-final -u.
