Struttura X-barra nei segmenti: la rappresentazione della lenizione

The article concerns some developments of Element Theory that extend X-bar theory to the realm of phonology in order to represent the internal structure of segments. While maintaining some fundamental assumptions of Element Theory concerning the nature of melodic primes, these models propose a radically diff erent conception of the segment and of larger phonological domains compared to autosegmentalist approaches. The article discusses some issues emerging from the adoption of X-bar theory and notation with regard to the representation of lenition phenomena, and suggests that the complex hierarchical structure that according to these theories corresponds to a segment poses problems of descriptive adequacy and raises a general question about learnability.