Post-tonic vowel harmony in some dialects of Central Italy

In Central Italy several dialects display post-tonic regressive vowel harmony, by which post-tonic vowels copy all the features of the word-final vowel. On the basis of phonetic and phonological arguments I argue that the penultimate vowel of proparoxytones, the typical target of this process, is a prosodically weak position, which makes it a good target for assimilation. In some dialects harmony is active only if a liquid consonant intervenes between the trigger and target vowels; since in these dialects liquids do not contrast for place, underspecification can explain this asymmetry. Since place specification of non-liquid consonants is required in other varieties, which nevertheless display harmony across any intervening consonant, following Clements (2001) I argue that in this case some nodes of feature geometry are not active.