Italo-Romance Metaphony and the Tuscan Diphthongs
by Martin Maiden (University of Oxford)
The historical causes of general so-called ‘opening’ diphthongization of proto-Romance low mid vowels in stressed open syllables are an enduring matter of dispute in historical Romance phonology, the two principal positions being that the diphthongs originate in the assimilatory process of metaphony conditioned by following unstressed vowels, or that they are a matter of ‘spontaneous’ diphthongization associated with lengthening of the vowels. Most recent scholarship on the subject has tended to favour the latter view. This study, focusing on Tuscan (and thereby on Italian), reasserts the case for the former interpretation, critically reviewing older arguments and adducing new ones to show that the details of Tuscan open syllable diphtongization are significantly correlated with a metaphonic origin, despite claims to the contrary. In particular, I argue that the restriction of the generalized diphthongs to open syllables reflects the early conditions of metaphony, and that the occasional absence of the diphthongs in Tuscan systematically presupposes the historical absence of a metaphonizing environment. In conclusion, I reflect on the significance of my claims both for general Romance historical morphology and, particularly, for the place of Tuscan among the Italo-Romance dialects. The data also show how morphological analogy may play a significant role in the diffusion of the effects of sound change.