Summary

Although respective Central (= CIDs) and Southern (= SIDs) Italo-Romance dialects display peculiar linguistic features, they also share a substantial number of common isoglosses such that they can be classified as two subdivisions of the same geolinguistic unit. Some of these are simply represented by the absence of Tuscan features, such as diphthongization in open syllable or anaphonesis. Other features are idiosyncratic and are discussed within the main body of this article, such as: (a) the different types of vowel systems; (b) the two main patterns of metaphony; (c) propagation; (d) phonosyntactic doubling that is not sensitive to stress. Regarding the morphological phenomena present in these varieties, the encliticization of possessives and the loss of both of the future indicative and the present subjunctive will be discussed. With regard to (morpho)syntax, these varieties are known for: (a) the rise of a mass neuter (neo-neuter) class of nouns; (b) an alternating gender value; (c) the extensive use of a dedicated marker to encode the accusative case in highly referential nouns; (d) dual complementizer systems; (e) split intransitivity in auxiliary systems; (f) extensive participial agreement (as well as similar agreement in manner adjectives); and, (g) pseudo-coordination, among other notable phenomena.