Weak elements in cycles
The diachronic development of Modern Italian pronouns, in particular of the 3pl dative loro ‘to them’ (Cardinaletti 2010; Egerland 2010), could be seen as the first step in a linguistic cycle in which elements become more and more structurally deficient, going from strong XPs, through weak deficient XPs, and finally to clitic X°s. However, historical data from Old Tuscan varieties show that there is much distributional instability and variation which is not easily accommodated in Cardinaletti and Starke’s (1999) tripartite typology. It will be claimed that the diachronic development of dative loro can be captured in terms of a close interaction between the internal structure of pronouns (where reanalysis as upward movement and the Head Preference Principle derive different degrees of structural deficiency), and general rules governing sentence structure.